It was while he was at Yale, that he got interested in acting. Whitmore joined the Yale Drama School Players and help co-found the Yale radio station. In 1942, he was drafted into the U.S. Marine Corps. During boot camp, Whitmore completed his degree and eventually became an officer.

In 1946, following his discharge, Whitmore joined the U.S.O. and studied acting at the American Theater Wing. He also gained experience in summer stock and other stock theatre companies.

In 1947, he made his professional acting debut with a stock company in Peterborough, New Hampshire. During the same year he also made his Broadway debut in Command Decision - a performance which earned him a Tony Award. After a number of years away, in 1970 he returned to Broadway in an unsuccessful production - Inquest. After this, Whitmore began to specialise in one-man shows.

One-man shows included Give 'Em Hell, Harry - as Harry S. Truman (1975 - filmed and released theatrically earning Whitmore, Golden Globe and Academy Award nominations for Best Actor), Bully! - as Theodore Roosevelt (1977 - production was filmed and released theatrically), and Will Rogers U.S.A. - as Will Rogers, which premiered at Ford's Theatre in 1970. Will Rogers U.S.A. was later broadcast as a TV special in 1972 and Whitmore toured in the show on and off for the next thirty years. His final performance as Will Rogers was in February 2000.

In 1949, Whitmore made his film acting debut in The Undercover Man. Films he appeared in included Battleground (1949) [where he received an nomination for the Academy Award for Best Supporting Actor]; The Asphalt Jungle (1950); Kiss Me Kate (1953); Them (1954); Oklahoma! (1955); Planet of the Apes (1968); Tora! Tora! Tora! (1970); The Shawshank Redemption (1994) and The Majestic (2001).

His film career was punctuated by a number of absences. In 1960 he appeared in Who Was That Lady? - it was his last film for seven years until he appeared in the western Chuka (1967). Another break from films occurred in the late '80s and early '90s. Once again it was for seven years. During his breaks from films Whitmore could be frequently seen either on stage or on television.

Whitmore made his television debut during 1947 in the show Kraft Television Theater. Over the years he has appeared in many TV shows as a guest star or cast member. Television shows he guest starred on included Gunsmoke, Zane Grey Theater, Rawhide, Tarzan, The Big Valley and The Practice. Shows that Whitmore starred in were The Law and Mrs. Jones - as Abraham Lincoln Jones (1960-62), My Friend Tony - as Professor John Woodruff (1969) and Temperatures Rising - as Dr. Vincent Campanelli (1972-74). He also appeared in a number of mini-series during the 1980s. His most recent television appearance was in the series Mister Sterling (2003), in which he received an Emmy nomination for Outstanding Guest Actor in a Drama Series.

In 1968, Whitmore guest starred in Bonanza, in the season nine episode To Die in Darkness. He played John Postley.

Over the years, Whitmore has won many awards - Golden Globes (1949), Grammy (1975), Theatre World Award (1947), CableACE Award (1989), Donaldson Award (1947) and an Emmy (1999). He has also narrated many documentaries and appeared as the spokesperson in a series of commercials for Miracle Grow. James Whitmore was one of the founding members of New York's Actor's Studio, where he ran workshops and gave acting lessons. One of his students was James Dean.

On the personal side, Whitmore was married twice. His first wife Audra Lindley was an actress and she appeared opposite him in the 1985 stage production of Handy Dandy after their divorce. His second wife is Noreen Nash. Whitmore has one son James Whitmore Jr.

Whitmore's first love is the stage and he is left-handed. He has been described as "the supporting players' Spencer Tracy" and has sometimes been mistaken for Tracy. His specialty has been and still is solo performances on stage, screen and television.

In a career that has lasted for more than fifty years, Whitmore has become well-known for playing men who are tough on the outside but are soft on the inside.

Sources:
Yahoo! Movies
Internet Movie Database
What A Character!
Lycos Entertainment
Hollywood.com