As part of Steve Allen's re-work of the Tonight Show, Williamson went on tour with performers including Joe Williams, Rosemary Clooney, Paul Smith, Louis Nye and Bill "Jose Jimenez" Dana.
In the 1990s, Williamson performed with Don Rickles, Bob Newhart, and Joan Rivers; he regularly played the drums for Grammy-nominated jazz vocalist Ernestine Anderson and eventually became her musical director.
[citation needed] Williamson helped to create a non-profit organization for music performance and education in North Bend, Washington, named JazzClubsNW.
He was the graduate jazz and percussion assistant at Central Washington University for two years.
[3] In 2019, Williamson published a 62-page book called Jazz Traditions A Collection of Drum Set Teaching.