In common with fellow American screen icon James Stewart, Cagney became so familiar to audiences that they usually referred to him as "Jimmy" Cagney--a billing never found on any of his films. While technically incorrect, the use of the 'nickname' was a testimony to Cagney's impact.

Cagney was born in New York City to James Cagney Sr., an Irish American bartender and amateur boxer, and Carolyn Nelson, a Norwegian ship captain's daughter. The red-haired, blue-eyed Cagney graduated from Stuyvesant High School in New York City in 1918 and attended Columbia University.

He worked in vaudeville and on Broadway, marrying the dancer Frances Willard (aka: "Billie") Vernon (1899 - 1994) on September 28, 1922 and remained faithfully married for 64 years. They adopted a son James Cagney Jr and a daughter Cathleen "Casey" Cagney. When Warner Brothers bought the film rights to the play Penny Arcade they took Cagney and his co-star Joan Blondell from the stage to the screen in the retitled Sinner's Holiday (1930).

The five-five, 180-pound Cagney went on to star in numerous films, making his name as a 'tough guy' in a series of crime films beginning with the smash hit classic The Public Enemy (1931), then continuing with Smart Money (1931), his only film with Edward G. Robinson (shot before The Public Enemy was released and made him an immediate sensation), Blonde Crazy (1931), and Hard to Handle (1933). He later played fictional gangster Rocky Sullivan in Angels with Dirty Faces (1938), worked as a gangster opposite Humphrey Bogart in The Roaring Twenties, won an Oscar playing George M. Cohan in Yankee Doodle Dandy (1942), returned to his gangster roots in Raoul Walsh's masterful White Heat (1949) ("Made it, Ma! Top of the world!"), and played the lunatic ship captain opposite Jack Lemmon and Henry Fonda in Mister Roberts (1955).

He was one of the founders of the Screen Actors Guild and president of the Guild from 1942-44.

Cagney's final appearance on film was in Ragtime in 1981, capping a career that covered over seventy films, although his last film prior to Ragtime had been 20 years earlier in 1961 with Billy Wilder's One, Two, Three, still regarded as the fastest-paced performance ever recorded on film. During this hiatus Cagney rebuffed all film offers, including a substantial one in My Fair Lady as well as a blank check from Charles Bluhdorn at Gulf & Western to play The Godfather, to devote time to learning how to paint (at which he became very accomplished), and tending to his beloved farm in Stanfordville, New York.

In 1974 he received the Lifetime Achievement Award of the American Film Institute and in 1984 his friend Ronald Reagan awarded him the Presidential Medal of Freedom.

Cagney's health deteriorated substantially after 1979, and the role in Ragtime, as well as a later television appearance in 1984, was designed to aid in his convalescence.