Kari Eloranta played in his native Finland until the age of 25 when he decided to try his hand at the NHL. In 1981-82, he suited up for 19 games with the Calgary Flames, picking up five assists. He played the rest of the year in Oklahoma City of the CHL, scoring three goals and 27 assists in 39 games.
In 1981-82, he was sent to the St. Louis Blues after 19 games in a Flames' uniform. His career with the Blues lasted all of 12 games. By the 1982-83 season, Eloranta was back in Calgary where he played all 80 games. He contributed four goals and 40 assists. Eloranta played three more years with the Flames before leaving the NHL after the 1986-87 season to return to Europe.
In 1989-90, Eloranta made a one-year stop in Lugano where he played in the Swiss Elite League, scoring seven goals and 25 assists in just 35 games. He then returned to his home country, to play with Reipas Lahti. In 44 games, Eloranta had seven goals and 25 assists.
At the age of 38, Eloranta came out of retirement to play another season in the Swiss Elite League, participating in 17 games with Rogle Angelholm