In his autobiography, Cagney said that as a young man, he had no political views, since he was more concerned with where the next meal was coming from.
 However, the emerging labor movement of the 1920s and 1930s soon forced him to take sides.
The first version of the National Labor Relations Act was passed in 1935 and growing tensions between labor and management fueled the movement.
Fanzines in the 1930s, however, described his politics as "radical".

This somewhat exaggerated view was enhanced by his public contractual wranglings with Warner Bros. at the time, his joining of the Screen Actors Guild in 1933, and his involvement in the revolt against the so-called "Merriam tax".
The "Merriam tax" was an underhanded method of funnelling studio funds to politicians; during the 1934 Californian gubernatorial campaign, the studio executives would "tax" their actors, automatically taking a day's pay from their biggest earners, ultimately sending nearly half a million dollars to the gubernatorial campaign of Frank Merriam.
Cagney (as well as Jean Harlow) publicly refused to pay and Cagney even threatened that, if the studios took a day's pay for Merriam's campaign, he would give a week's pay to Upton Sinclair, Merriam's opponent in the race.

He supported political activist and labor leader Thomas Mooney's defense fund, but was repelled by the behavior of some of Mooney's supporters at a rally.
Around the same time, he gave money for a Spanish Republican Army ambulance during the Spanish Civil War, which he put down to being "a soft touch".
This donation enhanced his liberal reputation.
He also became involved in a "liberal group...with a leftist slant," along with Ronald Reagan.
However, when he and Reagan saw the direction the group was heading, they resigned on the same night.

Cagney was accused of being a communist sympathizer in 1934, and again in 1940.
The accusation in 1934 stemmed from a letter police found from a local Communist official that alleged that Cagney would bring other Hollywood stars to meetings.
Cagney denied this, and Lincoln Steffens, husband of the letter's writer, backed up this denial, asserting that the accusation stemmed solely from Cagney's donation to striking cotton workers in the San Joaquin Valley.
William Cagney claimed this donation was the root of the charges in 1940.
Cagney was cleared by U.S. Representative Martin Dies Jr. on the House Un-American Activities Committee.

Cagney became president of the Screen Actors Guild in 1942 for a two-year term.
He took a role in the Guild's fight against the Mafia, which had begun to take an active interest in the movie industry.
His wife, Billie Vernon, once received a phone call telling her that Cagney was dead.
Cagney alleged that, having failed to scare off the Guild and him, they sent a hitman to kill him by dropping a heavy light onto his head.
Upon hearing of the rumor of a hit, George Raft made a call, and the hit was supposedly canceled.

During World War II, Cagney raised money for war bonds by taking part in racing exhibitions at the Roosevelt Raceway and selling seats for the premiere of Yankee Doodle Dandy.
He also let the Army practice maneuvers at his Martha's Vineyard farm.

After the war, Cagney's politics started to change.
He had worked on Democrat Franklin D. Roosevelt's presidential campaigns, including the 1940 presidential election against Wendell Willkie.
However, by the time of the 1948 election, he had become disillusioned with Harry S. Truman, and voted for Thomas E. Dewey, his first non-Democratic vote.

By 1980, Cagney was contributing financially to the Republican Party, supporting his friend Ronald Reagan's bid for the presidency in the 1980 election.
As he got older, he became more and more conservative, referring to himself in his autobiography as "arch-conservative".
He regarded his move away from liberal politics as "a totally natural reaction once I began to see undisciplined elements in our country stimulating a breakdown of our system... Those functionless creatures, the hippies ... just didn't appear out of a vacuum."
In his autobiography, Cagney said that as a young man, he had no political views, since he was more concerned with where the next meal was coming from.  However, the emerging labor movement of the 1920s and 1930s soon forced him to take sides. The first version of the National Labor Relations Act was passed in 1935 and growing tensions between labor and management fueled the movement. Fanzines in the 1930s, however, described his politics as "radical".
This somewhat exaggerated view was enhanced by his public contractual wranglings with Warner Bros. at the time, his joining of the Screen Actors Guild in 1933, and his involvement in the revolt against the so-called "Merriam tax". The "Merriam tax" was an underhanded method of funnelling studio funds to politicians; during the 1934 Californian gubernatorial campaign, the studio executives would "tax" their actors, automatically taking a day's pay from their biggest earners, ultimately sending nearly half a million dollars to the gubernatorial campaign of Frank Merriam. Cagney (as well as Jean Harlow) publicly refused to pay and Cagney even threatened that, if the studios took a day's pay for Merriam's campaign, he would give a week's pay to Upton Sinclair, Merriam's opponent in the race.
He supported political activist and labor leader Thomas Mooney's defense fund, but was repelled by the behavior of some of Mooney's supporters at a rally. Around the same time, he gave money for a Spanish Republican Army ambulance during the Spanish Civil War, which he put down to being "a soft touch". This donation enhanced his liberal reputation. He also became involved in a "liberal group...with a leftist slant," along with Ronald Reagan. However, when he and Reagan saw the direction the group was heading, they resigned on the same night.
Cagney was accused of being a communist sympathizer in 1934, and again in 1940. The accusation in 1934 stemmed from a letter police found from a local Communist official that alleged that Cagney would bring other Hollywood stars to meetings. Cagney denied this, and Lincoln Steffens, husband of the letter's writer, backed up this denial, asserting that the accusation stemmed solely from Cagney's donation to striking cotton workers in the San Joaquin Valley. William Cagney claimed this donation was the root of the charges in 1940. Cagney was cleared by U.S. Representative Martin Dies Jr. on the House Un-American Activities Committee.
Cagney became president of the Screen Actors Guild in 1942 for a two-year term. He took a role in the Guild's fight against the Mafia, which had begun to take an active interest in the movie industry. His wife, Billie Vernon, once received a phone call telling her that Cagney was dead. Cagney alleged that, having failed to scare off the Guild and him, they sent a hitman to kill him by dropping a heavy light onto his head. Upon hearing of the rumor of a hit, George Raft made a call, and the hit was supposedly canceled.
During World War II, Cagney raised money for war bonds by taking part in racing exhibitions at the Roosevelt Raceway and selling seats for the premiere of Yankee Doodle Dandy. He also let the Army practice maneuvers at his Martha's Vineyard farm.
After the war, Cagney's politics started to change. He had worked on Democrat Franklin D. Roosevelt's presidential campaigns, including the 1940 presidential election against Wendell Willkie. However, by the time of the 1948 election, he had become disillusioned with Harry S. Truman, and voted for Thomas E. Dewey, his first non-Democratic vote.
By 1980, Cagney was contributing financially to the Republican Party, supporting his friend Ronald Reagan's bid for the presidency in the 1980 election. As he got older, he became more and more conservative, referring to himself in his autobiography as "arch-conservative". He regarded his move away from liberal politics as "a totally natural reaction once I began to see undisciplined elements in our country stimulating a breakdown of our system... Those functionless creatures, the hippies ... just didn't appear out of a vacuum."
James Cagney