With the Greece men's national team, he competed in six consecutive EuroBasket tournaments, (1993, 1995, 1997, 1999, 2001, and 2003), and he made it to the semifinals on the first three occasions.

In 1997, while playing with Olympiacos, Sigalas won the European basketball Triple Crown, meaning his team won the Greek League championship, the Greek Cup title, and also the European-wide top-tier level EuroLeague championship, all in the same season.

Sigalas left Olympiacos Piraeus in 1997, after winning the EuroLeague championship with them, and he then joined the Italian League team Olimpia Milano.

Sigalas returned to the Italian League, to play with Viola Reggio Calabria, at the end of the 2002–03 season.

Sigalas made his U18 international debut with the Greece men's national under-18 basketball team at the 1990 FIBA Europe Under-18 Championship, and the Greece men's national under-20 basketball team won a silver medal at the 1992 FIBA Europe Under-20 Championship.

[4] In January 2020, Sigalas was hired as the assistant coach of Ilias Kantzouris, for Greek Basket League club Iraklis Thessaloniki.