Sigalas won five consecutive Greek League championships while playing with Olympiacos from 1993 to 1997. He also won 2 Greek Cups with Olympiacos in 1994 and 1997. In 1997, while playing with Olympiacos, Sigalas won the Triple Crown, meaning his team won the Greek League championship, the Greek Cup, and the Euroleague championship all in the same year, the only time it has happened in club history.
In the last years of his career, he returned home to play in the Greek League to finish his career. He played with Makedonikos in the 2003-04 season, Panionios in the 2004-05 season, and finally, Sigalas ended his career back with Aris, where he played from 2005, until he retired in the year 2007.
Since retiring, Sigalas worked as a basketball commentator in Greece for Euroleague games. He also worked as a coach for the national youth Greek basketball teams. He also coached Ermis Lagada during the 2009-10 season.