The Polish international midfielder joined Chicago in 1998 after a four-year tenure with 1860 Munich that saw him named Poland's Player of the Year (1996) and the Bundesliga's best playmaker (1995-96). He made an immediate impact with the fledgling MLS side, who named him the team MVP in his first season as they won the MLS Cup and the US Open Cup.
More successes followed, including another US Open Cup in 2000, as Nowak collected two more MVP awards in 2000 and 2001. By the end of the 2002 season, he set the club's current all-time assist record at 48. But salary cap considerations led Chicago to trade their then-38-year old captain to New England for the 2003 season. Later that year, Chicago made him the first inductee in their "Ring of Fire," honoring past players.
Just over one month after the trade announcement, Nowak chose to retire rather than continue his playing career in New England. He wasn't done with football altogether, however, as he took over as manager of DC United in 2004, winning that season's MLS Cup. He left DC in 2006 to work with the US national team and, in 2009, became the first head coach for the Philadelphia Union. He later took charge of Antigua and Barbuda and is currently the manager of Polish club Lechia Gdańsk.