After the war, Markowitz studied music in Paris and under Arthur Honegger and Arnold Schoenberg.
He collaborated again with Kernsher on the films The Young Captives, (1959), Hoodlum Priest (1961), and Face in the Rain (1963).
He collaborated with his wife on the score of the film Roadracers (1959) where Haru wrote lyrics to the songs.
His other film scores included One Man's Way (1963), Bus Riley's Back in Town (1965), Wild Seed (1965), Ride Beyond Vengeance (1966), The Shooting (1966), which starred Warren Oates and Jack Nicholson, Cry for Me, Billy (1972), and Circle of Power (1981).
Keeping with the Western genre he scored the television movie (Scalplock) that spawned the series The Iron Horse as well as providing music for a variety of American television series and made for TV movies such as Weekend of Terror (1970), The Hanged Man (1974), Brinks: The Great Robbery (1976), Mayday at 40,000 Feet!