His most successful recording was 1975's "Rocky"; a transatlantic Top 40 hit single.

He also wrote several songs that featured in episodes of Scooby-Doo Where Are You!

Roberts performed the theme song to the second season of the animated series, Scooby-Doo, Where Are You!

[citation needed] In 1972 he sang the hit "Something's Wrong With Me", written by Danny Janssen and Bobby Hart, which reached No.

15 single for Helen Reddy in April 1974, was another hit for Roberts, reaching No.