[1][2] Throughout his career, St. John has also toured as lead vocalist for notable hard rock acts such as: Kingdom Come,[3] Lynch Mob, The Neal Schon Band, Tracii Guns’ L.A.
Atlantic head of A&R Jason Flom's new found band, Big Trouble, featured St. John as lead vocalist, drummer Bobby Rondinelli, guitarist Jon Levin, and bassist Tommy Henriksen.
[citation needed] Throughout the late 1990s and 2000s, St. John was approached by many of Los Angeles' rock artists, managers, and record labels to sing and collaborate on up-and-coming projects.
St John also co-wrote and recorded the album Immoral Fabric with the band Medicine Wheel which featured guitarist Marc Ferrari and drummer Ray Luzier.
Some touring highlites include performing at the Woodstock 40th Anniversary at Golden Gate Park in San Francisco where the opened their set with The Who's "My Generation," and being billed over the years with iconic arena bands such as Journey, Def Leppard, The Scorpions, Cheap Trick, Sammy Hagar, Lynyrd Skynyrd, Whitesnake, Dokken and many other rock legends.
[11][12][13] Ronnie Montrose reportedly took his own life on March 3, 2012, after which St. John performed at a grand memorial concert in his honor at the Regency Ballroom in San Francisco.
Other performers included: Sammy Hagar, Neal Schon, Steve Smith, Joe Satriani, Denny Carmassi, Eric Singer, and Tommy Thayer.
Keith St. John and Doug Aldrich also performed a tribute to Montrose at the Iridium Theater in New York City on April 30, 2012, which was streamed over the World Wide Web and included the Les Paul Trio with Anton Fig.
In 1998, Keith met guitarist Doug Aldrich and the two demo'd their first few songs for the Japan-based record label Pony Canyon for what was to evolve into the band Burning Rain.
Keith and George wrote and recorded songs for Lynch's 2011 solo album Kill All Control which received critical acclaim from Rock and Heavy Metal reviewers.
St. John's most significant live performance with Lynch Mob came in 2014 before a packed house at the Saitama Super Arena in Tokyo Japan which holds approximately 36,000 people.