A native of Vihti, Finland, Eeli was selected 30th overall in the 2017 NHL Entry Draft by the Nashville Predators. Tolvanen began his professional career with Espoo in Finland’s Jr. A league in 2014-15 before moving to North America to further his development. He scored 17 goals in 49 games with Sioux City of the United States Hockey League in 2015-16, making the USHL All-Rooke Team, and increased that total to 30 in 53 games the following season when he made the First All-Star Team.

Playing for Finland at the 2016 IIHF World Junior Championship, he had seven goals in seven games to help win the gold medal.

In 2017-18, Tolvanen played in the Kontinental Hockey League with Jokerit, finishing with 36 points (19 goals, 17 assists) in 49 games and seven points (six goals, one assist) in 11 playoff games. He had a hat trick in his first KHL game on Aug. 23 and was voted to the KHL All-Star Game.

After signing a three-year, entry-level contract with the Predators on March 29, 2018, Tolvanen made his NHL debut three days later.

Tolvanen also represented Finland at the 2018 PyeongChang Olympics and had nine points (three goals, six assists). He was named to the Olympic All-Star team, although Finland finished sixth.