In 2003, he enrolled at Northwest Missouri, but did not play; he was granted a medical hardship after suffering a broken bone in his right foot in August camp.

He started twelve games at right defensive end and recorded 48 tackles (19 solos) with 8.5 sacks and 13 stops for losses.

In 2005, as a senior, he started fourteen games at right defensive end, recording 58 tackles (38 solos) with a team-high 16.5 stops for losses and five quarterback pressures.

He set a school single-season record, and ranked 13th in the nation, with 12.5 sacks, caused a fumble, blocked a kick, and deflected four passes.

At Northwest he was coached by Mel Tjeerdsma, who took the Bearcats to five consecutive NCAA Division II Football Championship title games between 2005 and 2009.

[6] Tollefson played with the NFL Europa team Berlin Thunder under a futures contract he signed with the Oakland Raiders.

Tollefson was also activated for all four of the Giants postseason games, and during the NFC Divisional Playoff against the Dallas Cowboys he recorded 2 assisted tackles and a QB hurry.

On September 11, 2011, Tollefson started his season with the Giants in place of Justin Tuck against the Washington Redskins, recording two tackles and a sack.

His sack dance is composed of an intentionally comical round-house spin kick (a homage to Patrick Swayze's role in Road House).