The eldest of three children, Forsythe was born as John,[REF][REF][REF] or Jacob, Lincoln Freund (sources differ) on January 29, 1918, in Penns Grove, New Jersey, to Blanche Materson (née Blohm) and Samuel Jeremiah Freund.
He was raised in Brooklyn, New York, where his father worked as a Wall Street businessman during the Great Depression of the 1930s.