Pyznarski grew up on the South side of Chicago, attending Marist High School.

After a successful career in Minor League Baseball, highlighted by The Sporting News Minor League Player of the Year Award and Topps Minor League Player of the Year Award in 1986, Pyznarski had a brief stint in the majors, appearing in 15 games for the 1986 San Diego Padres, where he compiled a .238 batting average (10-for-42).

He went into the metal finishing industry as a salesman a few years after retiring from professional baseball.

He played in MLB for the San Diego Padres (1986) and the Modesto A's (1981), West Haven A's (1982), Albany A's (1983), Tacoma Tigers (1984), Las Vegas Stars (1985–86), and Denver Zephyrs, Rochester Red Wings and Omaha Royals.

His 1987 Topps baseball card stated he was 6'2", weighed 195 pounds and batted and threw right handed.