Matsuda has black hair and brown eyes. His hair hangs over his ears with bangs that hang primarily above his right eye. After the time skip his hair is shorter, though there is more hair covering his forehead. He has fair skin and is of average height.
Matsuda's police skills are lacking in experience, and at times, particularly in the beginning of the series, he somewhat impedes the investigation process. Much to the irritation of his peers, his brash attitude can get him into tricky situations, as evidenced by the time he infiltrated Yotsuba and had to fake his own death to get out. Members of the Task Force, such as Ryuzaki and Shuichi Aizawa, seem to view him as a reckless, naive young detective lacking seriousness for his work.
Despite not having much experience in the NPA, Matsuda has proven to be useful or even crucial to the success of a mission, particularly after the timeskip, in which he helped bring down the Mafia members who were holding the Death Note. Showing great proficiency in his almost instant reactions to tight situations, Matsuda has demonstrated skill in the field of infiltration both as Misa Amane's manager Taro Matsui (松井 太郎, Matsui Tarō), and in the faces of the Yotsuba Group.
Matsuda appears to stay up to date with what is popular in the media, evidenced by his knowledge of Misa-Misa's achievements, and he often watches television. Remarkably, his television habit can be a resourceful asset to the investigation team.
Despite his naive personality, Matsuda maintains loyalty to the Task Force through many dangerous situations and commits to the NPA after the Kira case is solved. He is also totally devoted to Soichiro Yagami, who appears from the beginning of the series to have taken young Matsuda under his wing.
Matsuda is a skilled shot, shown when shooting the notebook out of the hand of a Mafioso without killing him and shooting the pen out of Light Yagami's hand when he attempts to write Near's real name on a hidden piece of the Death Note.
Matsuda has sympathy toward Kira's followers and thinks Kira had good intentions at heart but simply went about them the wrong way. His positive relationship with Light, however, seems all but forgotten after Light's confession, when Matsuda, out of anger and betrayal, shoots Light several times at the warehouse. His anger is partly caused by Light's lack of regret about his father's death.
Matsuda is a self-confessed weakling who, as a policeman, is duty-bound to capture Kira but also sees some of the benefits of a new world order where crime and war are almost non-existent.
In spite of his weak nature, he is prepared to take risks. When it becomes clear that Kira is targeting not just criminals but also the people who are after him, Matsuda is one of the few of the originally large Kira Investigation Team willing to stay and risk his life in order to catch Kira. Later, he takes big risks in infiltrating the Yotsuba Group building and eavesdropping on the secret meeting held by some of its executives as they discuss how to use Kira's powers for their own ends. He even agrees to act as bait in order to expose Kyosuke Higuchi as the Yotsuba Kira, even though he is aware that any slip-up in the plan may cost him his life.
Years later, when Mello acquires the Death Note, he contacts Soichiro Yagami and threatens to kill his daughter Sayu unless Soichiro reveals the identity of the current L (Light Yagami). Torn between both his children, Soichiro hesitates, but Matsuda gets him to tell Mello that he, Matsuda, is L but is quite "useless" (Matsuda's words), though Soichiro is more diplomatic by telling Mello that L-Matsuda merely follows the orders of others in the Kira Investigation Team. Matsuda then fears he'll be killed by Mello but isn't since Mello himself sees the current L as useless and not the real brains of the team.
When Light decides to get the Death Note back from Mello by entrusting the team with another, he knows that it will be necessary to make a deal for the Shinigami Eyes in order to get Mello's real name. This will involve the human bearer giving up half his life expectancy. Light expects Matsuda to volunteer for this and indeed he does, but ultimately Soichiro insists on making the eye deal instead.
During his first ICPO meeting, which was centered around the recent Kira case, Matsuda had no knowledge about the "L" figure the ICPO turned to help to for the Kira case, with Soichiro Yagami, the chief of the Task Force, explaining L to him.
During one of the Task Force's first meetings, Matsuda expresses his reasons as to why Kira may be in the right, only for his points to be shut down by the evident disapproval of every other member. After the meeting, Soichiro proceeded to talk to Matsuda about him speaking up, also assuring Matsuda that bringing up the reasons why Kira isn't in the wrong entirely was not really a necessarily wrong course of action to take.
After the 12 FBI agents who were sent by L to investigate Kira were killed, a large portion of the Task Force had quit the investigation. However, Matsuda, along with Soichiro, Mogi, Ide, Ukita, and Aizawa, was one of the few people to have remained. Matsuda, along with the rest of the remaining members of the Task Force, had frequent meet-ups with L and Watari through a private, five-star hotel, where L explained his theories as well as his plans and defenses against Kira. From here on out, Matsuda adopted the alias, "Matsui". Throughout the investigation, Matsuda has been chastised by L and the Task Force for his somewhat juvenile view on the investigation.
When Light and Misa cleared their memories, Matsuda was quick to accept that Kira is not among them. During the time of the Yotsuba Kira as Kira, Matsuda wanted to be more useful for the investigation and so, while posing as Misa's manager, decides to head to the Yotsuba building and overhears useful information, but blunders and ends up being caught by the members. He proposes to have Misa appear in their commercials as an alibi for being here.
While stalling, Matsuda manages to get in contact with L, who informs Matsuda to fall off the building and fake his death in order to escape them. After a few hours, when Misa and her friends arrived to satisfy the members of Yotsuba, Matsuda, acting drunk, did a headstand on the edge of the balcony and "accidentally" fell off, only for Wedy and Soichiro to catch him using a mattress, while Aiber poses as his "dead" body, thus ensuring Matsuda's safety. Luckily, with his return, he had managed to gain info regarding the investigation.
After the Task Force had learned who the third Kira is, Matsuda played a pivotal part of the final plan, which involved him being featured on a Sakura TV talk show, where he plans to reveal Kira's identity, and "accidentally" reveals his face. This forces Higuchi to try and find out Matsuda's real name to attempt to kill him, with L attempting to find out how Higuchi kills, but to no avail. Higuchi, frustrated, goes directly up to the show, but he is eventually caught by L and the Task Force, where they successfully find the Death Note.
After L was killed, the Task Force now listens to Light as the new L. Five years later, Mello kidnaps Sayu Yagami in order to get a hold of the Death Note. During Light's plan to seize Mello and regain the Death Note, he has the Task Force gain his Death Note, and plans on having Matsuda make the deal for the Shinigami Eyes. However, Soichiro offers to do it in place of Matsuda, and they attack Mello's base. After Soichiro's death, despite Near's evidence for Light being Kira, Matsuda makes a conscious effort to believe otherwise, being excited when something proves Light isn't Kira, refusing to believe he is.
During the final confrontation taking place at the Yellow Box Warehouse, Matsuda and the remaining members of the Task Force witness Near's plan to take down Kira, finally proving Light is Kira once and for all. Matsuda, seeing Light monologue and attempt to escape pathetically, is infuriated at Light for being Kira, and shoots him multiple times, rendering him completely physically useless, with Ryuk eventually killing him.
In the manga, sometime after this incident, Matsuda formulates a theory that Near had used the Death Note on Mikami, and had also manipulated Mello into sacrificing himself, with this being immediately shut down by Ide. Matsuda also easily befriends the new Task Force member, Yamamoto.
In Never Complete One-shot, Matsuda was one of the few people that was able to see Ryuk who goes along with Minoru Tanaka's plan of selling the Death Note. While Ryuk was holding one of Minoru's message in front of Sakura TV's camera, Matsuda had recklessly charged in a live broadcast to tell the Japanese citizens to not buy Kira's power, while showing his police badge to imply any Japanese citizen that buys the Death Note would be arrested, and would be hoping that the Japanese government would take this issue seriously; this action had angered Matsuda's superiors as Matsuda's actions had made the issue at hand more believable. Matsuda was later scolded by his superiors, where Matsuda was told that the Japanese government would never be able to purchase the Death Note, and was later assigned to desk duty to keep him away from the media.
In other media
In the film series, Matsuda is played by Sota Aoyama. In the first two films, Matsuda's role and personality are similar to the manga and anime. When Light is cornered at the end of Death Note: The Last Name, Matsuda shoots Light while he is trying to use a piece of the Death Note that he keeps hidden in his watch.
In a spin-off short film, Matsuda is having trouble coming to terms with the end of the Kira case and that Light was Kira. Soichiro sends him a note to visit L, and Matsuda does so and brings L cake. But the meeting doesn't quite offer Matsuda the closure he needs, and he breaks down in the street.
Nine years later in Death Note: New Generation, Matsuda leads the Task Force, which is comprised of otherwise new members. He administers a polygraph test on Tsukuru Mishima, and once Mishima passes, Matsuda welcomes him to the Task Force. The Task Force continues to investigate murders that might be caused by a Death Note.
In Death Note: Light Up the NEW World, six notebooks fall to the human world 10 years after Light's death, leading to the return of the Kira murders. Matsuda joins the Task Force to track down Yuki Shien. While investigating Shien's supposed location, Matsuda hears a recording of Light's voice, and he goes to look for him where he finds pieces of Death Note paper with Matsuda's name and manner of death. As written, Matsuda dies "with a smile on his face" as he shoots himself. This is witnessed by his team, and leaves them shaken. Junrou Sugawara acts in fear and shuts down the Task Force, forcing the others to work independently.
In the drama, Matsuda still obtains his same role as in the anime; however, one difference is that he is a family friend of the Yagamis prior to the series as he informs Sayu and Light when their father is held hostage. He is also the one to inform Light about L's methods and skills.
In the end, as Light is attempting to kill Near by writing his name in the notebook, Matsuda at first pleads with Light to stop and barely manages to bring himself into shooting Light, in which he collapses over the sight of what he did. Light is then shot twice and incapacitated by Aizawa and Mogi. When Mikami sets the warehouse on fire, Matsuda tries to save Light but is pulled away by Aizawa.
In Death Note: The Musical, Matsuda is a member of the Task Force, although he is not named in the production. His name is provided on the Korean production credits and in the English lyrics for Change the World.
After the deaths of the FBI agents, the Task Force is given the choice whether or not to stay on the case. Matsuda chooses to stay, but he says that he thinks this will be his last case. When Ide expresses his desire to leave, Matsuda tells him to go.
Obata described Matsuda as "hard to predict and thus hard to draw." Obata said that Matsuda's character concept consisted of an "average young detective" and that Matsuda's character had "nothing unique about his features and his actions weren't consistent, so I didn't like him. [laughs]" Obata added that he was a "Matsuda-type" person and therefore did not like seeing "my own inconsistency" in Matsuda. Obata described Matsuda as the sole character who "looks younger" during the Near and Mello arc.
Light Yagami's relationship with Matsuda is rather complex and less professional in
comparison to the other task force members—excluding his father Soichiro Yagami. At the start of the series, Matsuda knew very little of Light and, even though he had met both of the Yagami children in the past, he merely knew him as Chief Soichiro Yagami's son. He gets closer to Light when Light joins the task force, even still trusting him when others begin to suspect him of being Kira. His attitude around Light is playful when it comes to issues involving women (Misa Amane or Kiyomi Takada). However, at the meeting with Near at the warehouse, when Light finally admits to being Kira, Matsuda shoots him several times with his gun. Ostensibly this is in order to prevent Light from killing anyone with a piece of the Death Note, but it is also out of anger at the way in which Light's actions caused the death of his own father, whom Matsuda respected and looked up to.
Soichiro Yagami is seen by Matsuda as some sort of a father figure or mentor and Matsuda frequently comes to him for advice or consults him on his doubts. Matsuda is the task force member who shows the chief the most sympathy during his voluntary imprisonment and sides with him when they split from L during the course of the investigation into the Yotsuba Group. At the end of the series, Matsuda is especially enraged that Light Yagami sees his late father as merely a foundation for his new world order.
Ryuzaki views Matsuda as a reckless, dimwitted idiot who impedes the Kira investigation and gives him little credit, though Matsuda does work well with Light in discovering that some recent Kira killings are linked to the interests of the Yotsuba Group conglomerate. During Misa's "lamest date ever," Matsuda breaks up a fight between L and Light by informing them that Misa's latest surge in popularity may get her a part in a major movie, to which L remarks, "Matsuda's acting stupid again." L even taunts Matsuda when Misa reveals how she got Kyosuke Higuchi to admit to being the Yotsuba Kira, calling it a "triumph" as compared to Matsuda's bungled infiltration of the Yotsuba Group HQ, even though his actions narrowed the number of suspects down to eight, a number which included Higuchi.
Shuichi Aizawa's personality is especially contrasting to that of Matsuda's, often resulting in humorous upsets where Aizawa yells at him for "not taking his job seriously," and Matsuda apologizes. When L announces that the Kira Investigation Team is moving to a new, permanent HQ, Aizawa announces his determination to capture Kira, naming all those present: L, Light and Soichiro Yagami, but Matsuda notes that he does not mention him by name. Despite Aizawa's frequent criticism, Matsuda seems to look up to him as a superior and consider him a friend.
Hideki Ide is often taunted by Matsuda, especially over his lack of a love-life. While eavesdropping on Light Yagami's meetings with Kiyomi Takada, Ide expresses frustration over the way the pair interact, discussing things other than the Kira case which is the prime object of the exercise, while Matsuda finds it very romantic. In the final chapter of the main series, Ide and Matsuda are shown hanging out together, with the former trying to convince the other to get himself motivated again and put behind the doubts he has about ending Kira's reign and returning the world to the way it was before.
Sayu Yagami meets Matsuda at a time when she is grown and mature and attending university. Matsuda appears to fall for her at this period, praising her and acting friendly, but she turns him down because he is too old for her and her parents are not keen on a relationship between her and a police officer.
Ryuk looks upon Matsuda as a loser and resents the idea of being linked to him when Light decides to entrust the Task Force with a Death Note prior to the raid on the Mafia hideout. Like the rest of the Task Force, Matsuda shows little fear of Ryuk when he becomes a daily fixture at their headquarters and even gives him apples. Matsuda presses Ryuk without any success to tell them the location of Kira's hideout.
Near is not trusted by Matsuda, especially when he puts forward the suggestion that Light may be Kira. Matsuda consequently assures Light that he will not share any of their findings with Near. A year after Light's exposure as Kira and subsequent death, Matsuda still resents the idea of working with Near, now the new official L, since he firmly believes that Near used the Death Note in order to manipulate Teru Mikami into exposing himself and Light as the current Kiras and shortly after committing suicide in prison.
- "Matsuda, you idiot" became a recurrent phrase throughout the anime. Multiple members of the Task Force have said it: Ryuzaki has said this on numerous occasions, and Light says it after he is shot by Matsuda in the final episode.
- In the anime, certain characters take on stylized hair colors while the viewer hears their thoughts; Matsuda's color is yellow.
- “You guys hit at the same time. Just call this one a draw.” (Crazy)
- “Why are you looking at me? It's not me.” (Number Two)
- “W-what? Is this the matter of winning or losing?” (Prediction)
- To Light (in the anime): “What was it all for then?!What about your father, what the hell did he die for?!”
- To Light: “You drove your own father to his death... now you're trying to turn it the other way around, saying they are the fools who got tricked?” (Intent to Kill)
- To Light (in the anime): “You drove your own father to his death...and now you're saying we are the fools?!” (Episode 37)
- To Yotsuba Group: “It's time for Matsui Taro! Showtime!” (Episode 19)