[4] After serving a tour of duty in Vietnam with the United States Air Force from 1965 to 1966, Keats attended the Yale School of Drama in 1969–1970.

He was nominated for an Emmy in 1977 for his role as the ruthless, Great Depression-era entrepreneur Jay Blackman, who clawed his way to the top of the "rag trade", or clothing business, in the 1977 miniseries Seventh Avenue.

He also portrayed Thomas Edison on the brink of inventing the electric light bulb in the science fiction TV series Voyagers!.

His film career included roles in The Friends of Eddie Coyle (1973), Death Wish (1974), The Gambler (1974), The Gumball Rally (1976), The Last Dinosaur (1977), Black Sunday (1977), The Ivory Ape (1980), Hangar 18 (1980), Silent Rage (1982), Turk 182 (1985), Badge of the Assassin (1985), and the 1982 TV movie of the Norman Mailer book The Executioner's Song.

Set on New York City's Lower East Side of the 1890s, Keats played Jake Podkovnik (late of Russia), an assimilated "Amerikaner".