Jillson played for Rhode Island high school power Mount Saint Charles Academy, before moving on to the University of Michigan.

He signed with the Sharks at the conclusion of his junior season, but did not leave Michigan until he graduated from college with a business degree.

He played sparingly for the Sabres, but was inserted into their lineup during the 2006 Stanley Cup Playoffs to fill one of the holes on their blueline created by injuries to Dmitri Kalinin, Teppo Numminen, and Henrik Tallinder.

[1] After an unproductive second season with Pardubice, Jillson chose to remain in the Czech Republic, dropping down a league to the 1. národní hokejová liga to sign a two-year contract with KLH Chomutov on June 27, 2011.

[2] Jillson scored 12 points in 52 games to contribute to Chomutov's promotion to the Czech Extraliga, despite the success he left his contract and was released as a free agent on May 1, 2012.