Schelhaas started his career playing bass for several prog rock bands in the Canterbury area before he finally started the softrock band "National Head Band" in 1970 and turned to playing keyboard. They released the album Albert One in 1971, but without any success. Next stop for Schelhaas was Gary Moore's band and the recording of the album Grinding Stone from 1973. After the recording, he left Moore to do solo projects.
In July 1975, Schelhaas was asked to play keyboard in the band Caravan after Dave Sinclair left them. Jan Schelhaas toured the world around with the band and recorded three albums: Blind Dog At St. Dunstans (1976), Better By Far (1977) and Cool Water, which wasn't released until 1994. The summer of 1978, Caravan had a break and Schelhaas accepted an offer to join Camel on their world tour for their album Breathless. At that time, the band also included Richard Sinclair and Dave Sinclair with whom he'd already played in Caravan.
Schelhaas worked with Camel until 1981, when he contributed to "I Can See Your House From Here" from 1979 and the album Nude from 1981.