Finger was drafted in the eighth round, 240th overall, by the Colorado Avalanche in the 1999 NHL Entry Draft. While playing junior hockey with the Green Bay Gamblers of the USHL, he was selected as the league's Defenceman of the Year for the 1999–2000 season. In the 2000–2001 season Finger played in the WCHA, where he was named St.Cloud's Outstanding Freshman Hockey Player. Finger resides in Calumet, Michigan during the summer and spends much of his time working out and fishing the streams near Lake Superior.
Finger made his NHL debut on February 20, 2007 against the Calgary Flames. He recorded his first NHL point on an assist on a Paul Stastny goal against the Columbus Blue Jackets on February 27. On March 1, 2008, Finger scored his first NHL goal off of Nikolai Khabibulin of the Chicago Blackhawks. Finger went on to play the final 22 games of the regular season with the Avalanche, and finished the season with one goal and four assists with 11 penalty minutes and a +10 plus/minus. He finished the season tied for second on the team in plus/minus, trailing only team leader Ken Klee with a +18. In May, the Avalanche signed Finger to a one-year free agent contract for the 2007–2008 season. In the 2007-08 season, Finger played 72 games with the Avalanche, scoring 8 goals and 19 points, and finishing a +12. He also played in five playoff games that season, recording 2 assists in that time.
On July 1, 2008 the Maple Leafs signed Finger to a 4 year deal worth $3.5 million per season. Finger's career with the Maple Leafs began on a rough note, as he missed seven games at the beginning of the 2008-08 season due to a foot injury.