Born on May 27, 1985, in Lempäälä, Finland, Anttila began his professional career in the Finnish Liiga with Ilves during the 2004–05 season. He later played for TPS before moving to the Kontinental Hockey League (KHL) with Metallurg Magnitogorsk and Jokerit, where he served as captain for several seasons. He also had a stint in the Swedish Hockey League (SHL) with Örebro HK. After his time in the KHL, Anttila returned to Liiga, playing for Oulun Kärpät before joining HIFK.
Anttila has been a cornerstone of the Finnish national team, affectionately nicknamed "Mörkö" (Bogeyman) due to his towering 203 cm (6 ft 8 in) height. He famously captained Finland to two IIHF World Championship gold medals in 2019 and 2022. During the 2019 tournament, he scored crucial goals, including the game-winner in the final against Canada. He also played a key role in Finland's historic Olympic gold medal victory at the 2022 Beijing Winter Olympics, where he again served as captain. His international success underscores his reputation as a big-game player and a respected leader on the ice.