"Mars Williams is an open-minded musician, composer and educator who commutes easily between free jazz, funk, hip-hop and rock, Mars has played and recorded with The Psychedelic Furs, Billy Idol, Massacre, Fred Frith, Bill Laswell, Ministry, Power Station, Die Warzau, The Waitresses, Kiki Dee, Pete Cosey, Billy Squier, DJ Logic, Wayne Kramer, John Scoffield, Charlie Hunter, Kurt Elling, Swollen Monkeys, Mike Clark, Jerry Garcia, Naked Raygun, Friendly Fires, The Untouchables, Blow Monkeys and virtually every leading figure of Chicago's and New York City's "downtown" scene.

John Zorn credits Mars as "one of the true saxophone players--someone who takes pleasure in the sheer act of blowing the horn. This tremendous enthusiasm is an essential part of his sound, and it comes through each note every time he plays. Whatever the situation, Mars plays exciting music. In many ways he has succeeded in redefining what versatility means to the modern saxophone player."

In 2001 Mars received a Grammy Nomination for Best Contemporary Jazz Record with his group Liquid Soul.

Despite his busy touring schedule with Liquid Soul and The Psychedelic Furs, Mars manages to stay active on the Chicago underground improvising scene. In recent years he has toured and recorded with the Peter Brötzmann Tentet, Switchback, Full Blast, Scorch Trio, the Vandermark 5, Boneshaker, Chicago Reed Quartet and Cinghiale, teaming him with such musicians as Ken Vandermark, Hamid Drake, Michael Zerang, William Parker, Ikue Mori, Kent Kessler, Fredric Lonberg Holm, Peter Brotzmann, Joe McPhee, Paal Nilssen-Love, Ab Baars, Mike Reed, Jeb Bishop, Harrison Bankhead, Dave Rempis, Kidd Jordan and Matts Gustafson.

He performs weekly in Chicago along with Jim Baker, Steve Hunt, and Brian Sandstrom in the improvising quartet "Extraordinary Popular Delusions". As a bandleader, he continues to perform and record CDs with his own free-jazz groups, the NRG Ensemble, Witches & Devils, Slam, XmarsX, Mars Trio, Boneshaker and The Soul Sonic Sirkus which features improvising musicians and aerial circus performers. Along with Die Warsau's Van Christie, Mars has started Ratking Music, a production company focusing on music for film and television.

In addition to performing and creating music, Mars has been an educator in the field of woodwinds and jazz improvisation for over thirty years. Mars held the position of Woodwind Instructor at Bard College for two years. In the last few years Mars has presented Master classes and clinics to a number of private and public institutions including, the University of Massachusetts, Amherst, the University of Chicago, Roosevelt University (Chicago, IL), and June Collins Smith Museum of Fine Art (Auburn, AL)."