In 1971 he graduated from the Military University of Technology (WAT) of Warsaw, after which he served for six years in the 2nd Artillery Brigade.

Between 1998 and 2000 he was the deputy commander of the Multinational Corps North East composed of forces of Poland, Czech Republic, Denmark, Estonia, Germany, Latvia, Lithuania and Slovakia.

Between April 2007 and January 2010, Pietrzyk served as Polish ambassador to Iraq (followed by Stanisław Smoleń).

From January 2010 till 2014, Pietrzyk served as Poland's ambassador to North Korea, followed by Krzysztof Ciebień.

[4] Pietrzyk received burns to about 20 percent of his body, including his air passageways, and was held in an artificial coma to reduce the pain.