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, John Scoffield, Charlie Hunter, Kurt Elling, Swollen Monkeys, Jerry Garcia, Naked Raygun 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.

Along with his busy touring schedule with Liquid Soul and The Psychedelic Furs, Mars manages to stay active on the international creative music scene. In recent years he has toured and recorded with the Peter Brötzmann Tentet, Scorch Trio, the Vandermark 5, Michael Zerang & The Blue Lights, Chicago Reed Quartet, Trio Red Space, and Cinghiale.

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, Moments Form Trio, Slam, XmarsX, Mars Trio, Boneshaker and The Soul Sonic Sirkus which features improvising musicians and aerial circus performers. 

Despite his busy touring schedule, Mars still manages to perform, record and self release 3 CD’s of his annual experimental Christmas project, “Mars Williams presents: An Ayler Xmas”. For the last 10 years Mars brings “An Ayler Xmas”, to select cities in the US & Europe, and features local improvisers from each host city. For these memorable concerts, Williams merges a variety of Christmas songs with the indelible repertoire of free-jazz titan Albert Ayler.
 
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).