Born 1976 in San Francisco, David grew up in Santa Cruz, California. David picked up the saxophone at the age of 8 years old. He attended Berklee College of music on full scholarship, where he studied with George Garzone and saxophone guru Joseph Viola (who also taught Michael Brecker, Brandford Marsalis and Charlie Mariano). While in Boston he worked with John Medeski, the Either Orchestra, Dave Holland, Clark Terry, Dominique Eade, Mick Goodrick, Danilo Perez, Bob Moses, The Four Tops, Ken Schaphorst, Jim Black, Matt Wilson. After finishing his studies David moved back to the West Coast, where for several years he led bands in the Bay Area featuring such notable players as Larry Grenadier, Eddie Marshal, Jeff Ballard, Kenny Brooks, Kenny Wollesen, Larry Scheider, Dred Scott, Charlie Hunter, Vince Wallace, Liberty Ellman, Dmitri Metheny, Mark Levine and Scott Amendola.
Eventually heading the call of New York City, Valdez moved east in the mid-nineties. There he worked with Kurt Rosenwinkle, Dave Fuiczynski Josh Redman, Josh Roseman, Ben Monder, Matt Otto, Art Lillard, Bob Mover, Brian Melvin, Heather Bennett, Jay Collins, Donny McCaslin, Peter Appelbaum and Ben Allison.
In 2000 David relocated to Portland, Oregon's thriving Jazz scene. Since moving to the Northwest he has worked with Nancy King, David Friesen, Alan Jones, Gary Smulyan, Rob Scheps, Glen Moore, Mel Brown, Dave Frishberg, Bert Wilson, Randy Porter and Robert Moore.