The shows have featured blues harmonica players such as James Cotton, Carey Bell, John Mayall and Charlie Musselwhite.

Since 2021, Hummel and documentary film maker Jeff Vargen have collaborated on a video podcast, 'Mark Hummel's Harmonica Party' with both interviews and live performances of 50 blues and rock musicians including Charlie Musselwhite, Elvin Bishop, Barbara Dane, Nick Gravenites, Duke Robillard, Country Joe MacDonald, Barry Goldberg, Magic Dick, Lee Oskar, Willie Chambers, Anson Funderburgh, Angela Strehli, Chris Cain and others.

[3] A number of jazz and blues artists had already made their mark on Hummel at this point in his early career, including Billie Holiday, Count Basie, Ella Johnson, Lester Young, Jimmy Reed, Little Walter, Muddy Waters, Big Walter Horton, Paul Butterfield, Sonny Boy Williamson II, and Charlie Musselwhite.

[3] Once established in the East Bay in the 1970s, Hummel started performing with Boogie Jake, Sonny Lane, Cool Papa Sadler, and Mississippi Johnny Waters.

[4] Since its inception the band has featured a number of popular performers before they became household names, such as King of the Hill creator and blues bassist Mike Judge.

Other noteworthy members include Jimmy Bott, June Core, Marty Dodson, Rusty Zinn, Ronnie James Weber, Chris Masterson, Charles Wheal, Steve Wolf, Randy Bermudes and Joel Foy.

[5] Over the years Hummel has also toured or recorded with Sue Foley, Charles Brown, Brownie McGhee, Willie "Big Eyes" Smith, Bob Stroger, Dave Myers, Jimmy Pugh, Kid Andersen, Ron Thompson, Junior Watson, Duke Robillard, Steve Freund, Billy Flynn and Frank "Paris Slim" Goldwasser.

Past tours have included Snooky Pryor, William Clarke, Billy Boy Arnold, Lazy Lester, Sam Myers, John Mayall, John P. Hammond, Elvin Bishop, Jason Ricci, Howard Levy, Corky Siegel, James Cotton, Charlie Musselwhite, Duke Robillard, Kim Wilson, Lee Oskar, Jerry Portnoy, Magic Dick, Rod Piazza, Paul DeLay, James Harman, Mitch Kashmar, John Primer, Huey Lewis, Bobby Rush and many others.

[11] As of 2012, Hummel toured with a California and Texas aggregation, 'Golden State Lone Star Revue', a group that featured Anson Funderburgh and Little Charlie Baty on guitars plus R.W.