[1] Born in Leipzig, Germany, and brought up in Nunthorpe, North Riding of Yorkshire, Gilmore left school at the age of 14 and started pursuing his dream of becoming an actor.

During his early career, he appeared in several stage musicals, including Lock Up Your Daughters and released a single, "Follow That Girl" (HMV POP 740), in 1960.

He played Macheath opposite Jan Waters as Polly in a 1968 production of the Beggar's Opera in London, in which both were praised for their portrayals.

[3] After achieving notice in the role of James Onedin, Gilmore felt he had become typecast as the rugged sea captain.

Gilmore also appeared in a Heartbeat episode, called "The Frighteners", during the Nick Berry era; his third wife, actress Anne Stallybrass was a regular in the series.