In 1953 at age 19, Marr left college and turned professional. He began his professional golfing career by accepting a position at Westwood Country Club in Westwood, New Jersey, in 1953. A short time later, Marr took a job as an assistant club pro to Claude Harmon at Winged Foot Golf Club in Mamaroneck, New York, where he began to blossom. He began playing regularly on the PGA tour in 1960, and in that year earned his first professional win at the Sam Snead Festival. A year later, he won the Greater Seattle Open Invitational and then the Azalea Open in 1962. Marr joined the elite in golf world in 1965 when he captured the coveted PGA Championship, was named to the Ryder Cup team and elected PGA Player of the Year.