He attended the Hackley School in Tarrytown, New York, and graduated in 1957. As a teenager, he developed a strong interest in acting and began seeking out opportunities in television during the 1950s.

Early Acting Career

Hamilton's early work included appearances on television series such as "The Veil," "The Adventures of Rin Tin Tin," and "The Donna Reed Show." These roles helped him gain exposure and experience in front of the camera. His breakout role came in 1959 with the lead in the film Crime and Punishment U.S.A., a contemporary adaptation of the Dostoevsky novel directed by Denis Sanders.

Hollywood Recognition and MGM Era

Impressed by Hamilton's performance in Crime and Punishment U.S.A., iconic Italian-American director Vincente Minnelli cast him in the 1960 film Home from the Hill. This marked the beginning of Hamilton’s fruitful association with Metro-Goldwyn-Mayer (MGM), where he became a fixture throughout the 1960s.

From 1960 to 1968, Hamilton starred in over a dozen films for MGM, solidifying his Hollywood status. Notable films from this period include Where the Boys Are (1960), Light in the Piazza (1962), and Your Cheatin’ Heart (1964), in which he portrayed country music legend Hank Williams.

Transition to Television and Personal Life

As film opportunities began to decline in the late 1960s, Hamilton transitioned to television. In 1969–1970, he starred in the drama series Harold Robbins' The Survivors alongside screen legend Lana Turner. Around this time, Hamilton briefly dated Lynda Bird Johnson, the daughter of U.S. President Lyndon B. Johnson, gaining considerable public attention.

He later married actress and model Alana Stewart in 1972. The couple had one son, Ashley Hamilton, who also pursued a career in entertainment. The marriage ended in divorce in 1975, though Hamilton and Stewart have remained on friendly terms over the years and even co-starred in the reality series Stewarts & Hamiltons in 2015.