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.
Sigalas left Olympiacos in 1997, after winning the Euroleague championship and joined the Italian League team Olimpia Milano. He played there during the 1997–98 season. He then returned to the Greek League the following year to play with Aris. He stayed with Aris until 2000, when he transferred to Aris' arch-rival PAOK, with whom he played with from 2000–02. Sigalas next played in the Spanish League with Granada, at the beginning of the 2002–03 season, and with the Italian League team Viola Reggio Calabria at the end of the 2002–03 season.
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.