Coach Mariusz is a 2-time Olympian for Poland and finished 5th in both the 1500 and 400 meter freestyle at the 1988 Olympic Games. In the prelims, for the 400 free, he set the Olympic Record. He enjoyed success at the collegiate level as well. As a freshman, he won the 1650 at NCAAs for the University of Arizona and came within 22 one hundredths of the NCAA record.
His transition to coaching started where his swimming career ended at the University of Arizona. From there, Coach Mariusz took the Head coaching job at Oregon State before moving to South Florida to head the University of Miami swimming program. Today, he is the Assistant Aquatics Director and Assistant Head Swim Coach at Pine Crest School. (Fort Lauderdale campus). Coach Mariusz is married to Dagmara and has a young daughter, Julia.