A versatile musician, Tomsen seeks out projects that broadens the reach of classical music. His principal teachers include Joel Krosnick, Timothy Eddy, Ronald Leonard, Dr. Richard Naill, Ko Iwasaki, and Robert DeMaine. Additionally, he has taken master classes with János Starker, Gary Hoffman, Lynn Harrell and many others. As an active chamber musician Tomsen has participated at the Taos School of Music, Aspen Music Festival, Norfolk Music Festival, and Kneisel Hall Chamber Music School and Festival. Additionally, he was awarded top prizes at the inaugural M-Prize Junior Chamber Competition, WDAV String Quartet Competition, and Saint Paul String Quartet Competition in 2016 with the Chimera Quartet. Tomsen studied at the Juilliard School where he was a Kovner fellow.

Tomsen performs on a 1926 Carl Becker Cello on loan from the Colburn Collection and a Giovanni Lucchi bow on loan from the Maestro Foundation.