Fatih Terim's side has now won its domestic league 19 times, making it the most successful team in the competition's history.
Galatasaray is the champion of Turkey for the second successive season after a 4-2 victory over Sivasspor sealed the league title.
Striker Burak Yilmaz scored twice, while midfielder Selcuk Inan was also on target with a double on a vociferous occasion at the Turk Telekom Arena.
The last 10 minutes did not go to plan, with the visiting side netting two consolation strikes and Umut Bulut receiving a red card, but by then the title celebrations were already well under way.
Fatih Terim’s team has now won the league 19 times in the club's history, with this success moving the team above Fenerbahce's 18 at the outright top of the all-time list. Besiktas comes third with 13 titles.
With three games left to play going into the weekend, Gala had held a seven-point advantage over rival Fenerbache, which had lost to Benfica in the Europa League semifinals earlier this week.
That meant Gala’s victory sealed the title, although ultimately even a defeat would have been enough as Aykut Kocaman’s side suffered a disappointing 2-0 defeat to relegation candidate Istanbul BB.
January signings Didier Drogba and Wesley Sneijder both started the match, with the Dutchman replaced on 58 minutes, while the Ivorian played the full game alongside Burak in attack.
Gala has won seven domestic games in a row and faces Fenerbahce next week with the title already in the bag before rounding off the league season against Trabzonspor.