2012 When District 54 Democratic Representative Gregory Schadone retired and left the seat open, O'Brien ran in the three-way September 11, 2012 Democratic Primary, winning with 868 votes (40.4%)[3] and won the November 6, 2012 General election with 3,356 votes (55.7%) against Independent candidate Kenneth Amoriggi.[4]
2010 O'Brien initially challenged District 54 Democratic Representative Schadone in the September 23, 2010 Democratic Primary, but lost to Representative Schadone,[5] who won re-election in the November 2, 2010 General election against Independent candidate Lance Mantia.[6]