Born in the Territory of Hawaii of Japanese ancestry in 1929, Shigeta studied drama at New York University. Before he could fully embark on a Business career, Shigeta enlisted to serve in the United States Marine Corps during the Korean War where he served for two-and-a-half years, and rose to the rank of Staff Sergeant.

In 1958 the Nichigeki Theatre in Tokyo exported their extravaganza Cherry Blossom Show to Australia with Shigeta as the male lead. The show was performed at the Empire Theatre in Sydney, Her Majesty's Theatre in Brisbane, the Theatre Royal in Adelaide, and Her Majesty's Theatre in Melbourne. The show was a big success, with one Australian reviewer writing about Shigeta, "... has matinee idol good looks and a soothing baritone voice that should send the record companies mad for his autograph on recording contracts."

Shigeta first came on screen in the U.S., in 1959 as Detective Joe Kojaku in The Crimson Kimono, a detective story that featured an interracial romantic triangle between Kojaku, his partner Sgt. Charlie Bancroft (played by Glenn Corbett), and Christine Downes (portrayed by Victoria Shaw). Shigeta's character was somewhat groundbreaking for the 1950s, an Asian detective played by an Asian actor with regular speech patterns, rather than a non-Asian made up to pass as Asian who speaks in broken English.

James Shigeta shared the 1960 Golden Globe Award for Most Promising Male Newcomer with actors George Hamilton, Troy Donahue and Barry Coe.

Shigeta guest starred in many television shows, beginning with Alcoa Premiere in 1961, as a Korean War era Chinese Communist who tortured star Lloyd Bridges. He continued to act in television up through Avatar: The Last Airbender in 2005.

In 1965, Shigeta worked with Raymond Burr in the Perry Mason episode "The Case of the Wrongful Writ", cast as Lawyer Ward Toyama who finds himself as the defendant. Shigeta worked with Raymond Burr two more times, in the 1969 Ironside episode "Love My Enemy", and the 1971 episode "No Motive for Murder" of the same series.

From 1969 to 1972, Shigeta had recurring appearances on the TV hospital drama Medical Center, in which he alternately appeared as the Resident Doctor and Doctor Osaka, for seven episodes. He played the role of Chief Resident in the series 1969 2-hour pilot U.M.C.

He also continued starring in films. In 1976, he portrayed the famous Japanese admiral Chūichi Nagumo in Midway. In 1988, he played the ill-fated corporate executive Joseph Yoshinobu Takagi in the action adventure film Die Hard. Cage II: The Arena of Death from 1994 pits star Lou Ferrigno against Shigeta's character of underworld crime boss Tim Yum Yum. Shigeta lent his voice to Disney's 1998 animated film Mulan.

Tomorrow's Child from 1982, with Shigeta as a medical assistant to Doctor Ed Flanders, dealt with the subject matter of a baby being brought to full term in a test tube.

In 2005, Shigeta received a "Visionary Award" from the Asian-American theatre organization, East West Players, at their annual anniversary gala in Los Angeles.

In 2006, Shigeta was among the actors, producers and Directors interviewed in the documentary The Slanted Screen, directed by Jeff Adachi, about the representation of Asian and Asian American men in Hollywood.

Shigeta died in his sleep on July 28, 2014 at the age of 85 in Beverly Hills.