While studying at the Prague Conservatory Mraz was deeply moved by the Voice Of America radio broadcasts of Willis Conover, who was his connection to a vast new world of possibilities across the ocean. During that time, he was performing with the top jazz groups in Prague. After finishing his studies, George went to Munich and played clubs and concerts throughout Germany and Middle Europe with Benny Bailey, Carmel Jones, Leo Wright, Mal Waldron, Hampton Hawes, Jan Hammer and others.
In the winter of 1969, George got a call from Dizzy Gillespie to join his group in New York. After a few weeks with Dizzy, George went on the road with Oscar Peterson for about two years. After that, he worked with the Thad Jones/Mel Lewis Orchestra for the next six years. In the late seventies, George worked with Stan Getz, New York Jazz Quartet, Zoot Sims, Bill Evans, John Abercrombie and for over ten years with Tommy Flanagan.
With his customary selflessness, Mraz allows as how he never demurred from approaching projects as a leader. "I always wanted to do some kind of projects on my own," Mraz insists, "I just never got around to it." And given the who's who of jazz masters who've made him their first call bassist for three decades (including the Thad Jones/Mel Lewis Orchestra, Dizzy Gillespie, Carmen McRae, Clark Terry, Stan Getz, Slide Hampton, Elvin Jones, Joe Henderson, and Joe Lovano among many others), that's hardly surprising. "After I left Tommy Flanagan in 1992 I had a lot more time to do things," George smiles, adding that "I wouldn't mind doing a few more."
After leaving Flanagan, George went on to work with Joe Henderson, Hank Jones, Grand Slam (Jim Hall, Joe Lovano, Lewis Nash), DIM (Directions In Music with Herbie Hancock, Michael Brecker, Roy Hargrove), Mc Coy Tyner, Joe Lovano and Hank Jones Quartet, Manhattan Trinity.
George Mraz has recorded with Oscar Peterson, Tommy Flanagan, Roland Hanna, Hank Jones, Charles Mingus, Thad Jones/Mel Lewis Orchestra, NYJQ, Lionel Hampton, Woody Herman, Toshiko Akiyoshi, Kenny Drew, Barry Harris, Tete Montoliu, Jimmy Rowles, Larry Willis, Richie Beirach, McCoy Tyner, Adam Makowicz, Jimmy Smith, Stan Getz, Zoot Sims, Pepper Adams, Art Pepper, Warne Marshe, Phil Woods, Grover Washington Jr., Archie Shepp, Dave Leibman, Joe Lovano, Jim Hall, John Abercrombie, Kenny Burrell, Larry Coryell, Dizzy Gillespie, Chet Baker, Art Farmer, Jon Faddis, Jimmy Knepper, Bob Brookmeyer, Jon Hendricks, Carmen McRae, Helen Merrill, Elvin Jones and many others.