Robertson was born in Peking, China while his father was the head of the Department of Medicine at Peking Union Medical College. Robertson took an interest in music at the age of 4 and started taking piano lessons. By the age of 7, he had already started to compose music.
After dropping out of college Robertson moved to Los Angeles where he played in night clubs and, during the day, made demos for publishers with Lou Dinning of the Dinning Sisters. By 1953, he began writing with Hal Blair and, the following year, published I Really Don’t Want to Know with Howard Barnes which went on to be recorded by Les Paul and Mary Ford, Tommy Edwards, Eddy Arnold and others.
Over the next few years, he had a number of other major hits including I Don’t Hurt Anymore (Hank Snow / 1954 / #1 Country), Hummingbird (Les Paul and Mary Ford / 1955 / #7) and Born to Be With You (Chordettes / 1956 / #5).
Along with his songwriting, Robertson went on to play piano, using his unique “slip-note piano” style for artists including Chet Atkins, Elvis Presley, Waylon Jennings, Nancy Wilson, Al Martino and Ray Price.
His songwriting success continued in the 60’s with Please Help Me, I’m Falling (Hank Locklin / 1960 / #8 Pop / #1 Country), Ringo (Lorne Greene / 1964 / #1) and Does My Ring Hurt Your Finger (Charley Pride / 1967 / #4 Country). He also had fourteen of his songs recorded by Elvis Presley.
Robertson became a member of the Nashville Songwriter’s Hall of Fame in 1972.