James Cagney

He gave money for a Spanish Republican Army ambulance during the Spanish Civil War, which he put down to being "a soft touch".

The Hollywood Caravan to Spain; 1937 Riette Kahn is shown at the wheel of an ambulance donated by the American movie industry to the Spanish government in Los Angeles, California, on Sept. 18, 1937. The Hollywood Caravan to Spain will first tour the U.S. to raise funds to “help the defenders of Spanish democracy” in the Spanish Civil War.

His joining of the Screen Actors Guild in 1933 coincided with his involvement in the revolt against the so-called "Merriam tax".

The "Merriam tax" was an underhanded method of funneling 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 was an Oscar winner, a dancer, boxer, painter, sailor with yachts on both coasts, farmer with a 750 acre farm in upstate New York, and 100 acre farm on Martha's Vineyard. He raised Morgan horses on the big farm, and was given an honorary agriculture, farming, and soil conservation from Florida's Rollins College

https://en.wikipedia.org/wiki/James_Cagney