Hasselhoff was born in Baltimore, Maryland to Dolores Therese (née Mullinix/Mullinix; died February 11, 2009), a homemaker, and Joseph Vincent Hasselhoff, a business executive. His family is Roman Catholic, of German, Irish and English descent. His great-great-grandmother, Meta, emigrated with her family to Baltimore from Volkersen, Germany, 30 kilometres (19 mi) from Bremen, in 1865.
He spent his pre-teen years in Jacksonville, Florida, and later lived in Atlanta, Georgia where he attended Marist High School. Hasselhoff made his theatrical debut at age seven in Peter Pan, and ever since his childhood dream was to have a career on Broadway. He graduated from Lyons Township High School in La Grange, Illinois in 1970. He was a member of speech team, senior discussion leaders, president of choir, captain of the volleyball team and held roles in several plays (including one lead role as Matt in The Fantasticks). He studied at Bates College and Oakland University and graduated with a degree in theater at the California Institute of the Arts.
Hasselhoff portrayed Dr. Snapper Foster on The Young and the Restless from 1975–82, leaving the series as the show wrote out many of their original characters. In 1979, he played Simon in Starcrash. He launched his singing career with guest appearances on the first season of children's program Kids Incorporated, performing Do You Love Me. He guest starred on an episode of Diff'rent Strokes and the soap opera Santa Barbara as himself in 1984.