Pniewski was born in Los Angeles, California. His education began at UCLA, where he graduated in 1983 with a Bachelor of Arts Degree in Theater and also won the Natalie Wood Acting Award.
From January 2002 until September 2004, he served as Georgia’s representative on the National Board of the Screen Actors Guild (SAG). He is currently the Atlanta Local First Vice-President of SAG-AFTRA.
Additional credits include Big Love, Thief, The Riches, Miami Vice, The Ultimate Gift, The Sopranos, Blue Bloods, CSI: NY, Conviction, Warm Springs, Buried Alive II, Spaceballs, One Tree Hill, CSI: Miami, ER, Runaway Jury, From the Earth to the Moon, Ray, Remember the Titans, and Two Soldiers, the 2003 Academy Award winner for Best Live Action Short Film.
Pniewski is also noted for his commercials and voice over work. His credits include Xerox, Ford, Buffalo’s, Wal-Mart, TNT, Bell South, Sprite, CNN, McDonald's, UPS, Hills Brothers, Georgia Power, Publix, Wachovia, Sudafed, Zoo Atlanta, Chevrolet, The Atlanta Thrashers, Miller Lite, SunTrust Bank, GTE, and Blockbuster Video.
