Born William “Billy” Millar July 4th, 1931 at White House by Belfast, Northern Ireland. His mother was Martha Boyd and his father a Canadian truck driver James Alexander Millar who worked for Fleming’s on Tomb Street in Belfast. Billy was one of nine children. Billy attended Glengormley & Ballyrobert primary school and then moved on to Ballyclare High School and studied bookkeeping at Hughes Commercial Academy.

As a young man Billy was a member of the Carnmoney Dramatic Society before joining the Ulster Theatre Group.

From 1955 to 1977 Billy travelled the world acting in more than 50 movies and TV shows. In 1956 he signed a seven-year contract with 20th Century-Fox. This led to his first film role, as an IRA member spying for the Nazis in The Man Who Never Was (1956), a job he was offered by legendary producer Alexander Korda. William Wyler was so struck by Boyd's performance in that film that he asked Fox to loan him Boyd, resulting in his being cast in what is probably his most famous role, that of Messala in the classic Ben-Hur (1959) opposite Charlton Heston. He received a Golden Globe award for his work on that film but was surprisingly bypassed on Oscar night. Still under contract with Fox, Boyd waited around to play the role of Marc Anthony in Cleopatra (1963) opposite Elizabeth Taylor. However, Taylor became so seriously ill that the production was delayed for months, which caused Boyd and other actors to withdraw from the film and move on to other projects.