He has worked with Sammy Hagar, David Lee Roth, Eddie Money, REO Speedwagon, Bad English, Guitar Shorty, Patty Smyth, and McAuley Schenker Group.
He lost interest in classical at that time, and in high school started playing the organ with a band called Zephyr, later Rags.
During the next few years Harms studied piano with some very good jazz teachers notably, Bill Bell (Carmen McRae), Tom Coster (Santana, Gabor Szabo) and Wilbert Baranco.
After moving to L.A., Harms spent the next year writing songs with Alphonso, forming a band that included Vinnie Appice (Dio, Black Sabbath) and Joe Turano (Michael Bolton) and making a record.
Ry asked Harms to play on his Borderline album and then signed John and his band to tour Europe as his backup musicians in the winter of 1980 to promote the record.
Soon after Harms got a call from producer Keith Olsen to do some additional recording on a single from Three Lock Box an album he had made for Sammy Hagar.
In late 1985 Harms focused on writing songs and in early 1986 hegot a call from Ted Templeman again to work on David Lee Roth's platinum Eat 'Em and Smile CD (Steve Vai, Billy Sheehan, Greg Bissonette).
His friend Dave Amato (Ted Nugent, Cher) was added on guitar and Brian Hitt (Wang Chung) on drums.
1990 was spent writing and touring with REO Speedwagon as well as recording their CD The Earth, A Small Man, His Dog And A Chicken, which Harms co-produced and included Live It Up which reached #6 on the Rock Chart and 5 more of his songs.
1991 through 1995 were spent in L.A. as a staff writer producing songs that appeared on CD's by Patty Smyth (Gold Record), Bad English (European #1), MSG, and Johnny Van Zandt etc.
In 2000 Harms co-produced, played keys and sang on Sammy's Ten 13 CD which included one of his songs and the band toured into 2001 to support the album.
Harms also wrote 3 songs, including the title track, on Guitar Shorty's follow up CD We the People which won the Handy Blues Award.