He was born as the younger brother of the actor Melvyn Douglas.
Their mother was Lena Priscilla (née Shackelford) and their father Edouard Gregory Hesselberg, a concert pianist and composer.
His mother, a native of Tennessee, was Protestant and a Mayflower descendant.
His maternal grandfather, George Shackelford, was a general and Civil War veteran.
He died in San Diego, California, United States, in June 1983.