Ethnicity: He has Pennsylvania Dutch (German), English, and Scottish ancestry; his mother was born in Lambton, Ontario.
Hackman was born on January 30, 1930, in San Bernardino, California, the son of Eugene Ezra Hackman and Anna Lyda Elizabeth (née Gray). He has one brother, Richard.
His family moved frequently, finally settling in Danville, Illinois, where they lived in the house of his English-born maternal grandmother, Beatrice. Hackman's father operated the printing press for the Commercial-News, a local paper. As a teenager, Hackman knew Dick Van Dyke, who was friends with his older brother Richard. His parents divorced in 1943 and his father subsequently left the family.
He left home at age 16 and lied about his age to enlist in the United States Marine Corps. His mother died in 1962 as a result of a fire she accidentally set while smoking.