Lonergan was selected with the No. 13 pick in the 2012 NAB AFL Draft and has played the past three matches since making his debut against Fremantle in round six.
The 18-year-old played his best game for the club against the Western Bulldogs on Saturday, racking up 17 disposals, three clearances and four tackles.
A graduate of the AFL- AIS Academy, Lonergan said he was thrilled to extend his contract.
"I’m rapt to have re-signed with the club. I’ve enjoyed the move to the Gold Coast and I’m loving my time up here," he said.
Lonergan’s contract extension coincides with fellow Tasmanian Henry Schade, who has also added two more years to his existing deal.
Schade was the Suns' first selection in the 2011 NAB AFL Draft at No. 24 overall.
The 196cm defender is a key position player who has focused on adding size to his frame while playing for the Suns reserves in the NEAFL.
Schade said he never had any doubt that he would recommit to Gold Coast.
"I’m working really hard in the gym and with our development coaches to make sure that I’m ready for senior football as soon as possible," he said.
Lonergan and Schade join teammates Jack Martin, Zac Smith, Trent McKenzie, Seb Tape, Rory Thompson, Jackson Allen, Clay Cameron and Charlie Dixon who have all recommitted in 2013.
Michael Whiting covers Gold Coast news for AFL.com.au. Follow him on Twitter: @AFL_mikewhiting
