The story follows Phoenix "Nick" Wright, a rookie defense attorney who attempts to have his clients declared "not guilty".

[18] During investigations, which usually take place before or between trial sessions, the player gathers information and evidence by talking to characters such as their client, witnesses, and the police.

The player can spray luminol by tapping areas they want to examine on the touch screen allowing them to see otherwise invisible blood stains.

[26] Phoenix Wright, a newly hired defense attorney at Fey & Co. Law Offices, agrees to represent his childhood friend Larry Butz who has been charged with the murder of his girlfriend Cindy Stone.

With the help of his boss and mentor, Mia Fey, Phoenix proves that Frank Sahwit, the prosecution's eyewitness, is the real murderer.

His reputation established, Phoenix takes on another case, this time defending Will Powers, the lead actor in the Steel Samurai children's TV show, against accusations that he killed his co-star Jack Hammer.

After relenting for Phoenix's help after an initial refusal, Wright faces Edgeworth's mentor Manfred von Karma, who has not lost a single case in his forty-year career.

Phoenix discovers that former bailiff Yanni Yogi shot Hammond with a gun provided by von Karma.

Unable to deal with a blemish on his record, von Karma murdered Gregory and manipulated Edgeworth into believing that he was responsible.

At the same time, Yogi was publicly blamed and convinced by Hammond, his attorney, to plead insanity, which got him acquitted of all charges at the cost of both his fiancée and social standing, leaving the truth hidden until the present day.

In a fifth case added for the Nintendo DS and subsequent releases, Phoenix is hired by Ema Skye to defend her older sister Lana, the head of the prosecutor's office, who is accused of murdering detective Bruce Goodman.

Together with Ema, Phoenix traces the origins of the murder to an incident two years ago, when serial killer Joe Darke allegedly murdered prosecutor Neil Marshall while trying to escape custody, but Phoenix also discovers a piece of evidence that implicates Ema as Marshall's killer.

[31][32][33] In 2000, after Takumi had finished his work on Dino Crisis 2, his boss, Shinji Mikami, gave him six months to create any type of game he wanted.

[32] Takumi cited Japanese mystery author Edogawa Ranpo as an inspiration, particularly The Psychological Test, a short story which involves a crime that "unravels due to the criminal's contradictory testimony."

"[37] Takumi felt the best way to write a mystery with a good climax is to reveal various clues, then pull them together into one conclusion, and not have multiple possible endings.

The classroom trial in the game's fourth episode is based on real events: when Takumi was in second grade, he had found a 5 yen coin and put it in his pocket; his teacher accused him of stealing it from another student and made him apologize to her.

In the end, Takumi changed the scriptwriter character to a director, and made the culprit a "strong, glamorous, fashionable, and cool-headed" producer.

[47][48] A PC port of the Game Boy Advance version, developed by Daletto, was released in Japan in an episodic format, beginning on March 18, 2008.

[54] The localization of the game was outsourced to Bowne Global, and handled by writer Alexander O. Smith, who was unfamiliar with the Ace Attorney series before working on it, and editor Steve Anderson.

[44] Michael Cole of Nintendo World Report said the game's design and interface would make it a good choice for non-gamers as well.

[18] Craig Harris of IGN felt the main issues with the game were its linearity, and how the puzzles are simple because the player can stop witness testimony at any time.

Bowskill called the investigation sections "tedious" and "boring" at times, but said they were outweighed by the "feeling of accomplishment" from solving the cases.

The cross-examination graphics, showing the two opposing lawyers along with the sound effect of a sword being unsheathed, she added, created an atmosphere similar to that of a fighting game.

[17] Harris agreed the visuals were well-drawn and called the soundtrack "nicely rendered", but felt the character animation was very limited.

He also appreciated the character development arcs through the game, which he felt provided pacing and made the cases cohesive.

[60] IGN's Craig Harris called it "incredibly lazy", wishing it had included improved art and sharper text.

[72] In 2016, Famitsu readers voted Gyakuten Saiban as the second best Game Boy Advance title, behind only Pokémon Ruby and Sapphire.

[73] In 2017, Famitsu readers voted Gyakuten Saiban the third best adventure game of all time, behind only Steins;Gate and 428: Shibuya Scramble.

[92][93] A manga based on the game, written by Kenji Kuroda and drawn by Kazuo Maekawa, premiered in 2006 in Bessatsu Young Magazine.

[97][98] A live action film adaptation of the game, titled Ace Attorney, produced at Toei Company, and directed by Takashi Miike, premiered in Japanese theaters on February 11, 2012.