The 23-year-old, who has experience playing either in the centres or on the wing, scored two tries in the Rhinos’ Boxing Day friendly victory over Wakefield.
“It was my ambition to earn a contract with the club when I came over here and I backed myself to do that so I am delighted to have signed for the season,” he said.
“It was a gamble to move here on a trial and away from everything I knew in Australia but the hard work has been worth it and I am pleased with my decision.
“I really enjoyed my first run out against Wakefield and the crowd and atmosphere at the Stadium was fantastic.
“I know there is still a lot of work to do and I want to prove I can step up and play in the Super League and I am really looking forward to getting out there again and the start of the season.”
The former St George junior joins the club from Gold Coast however spent the majority of his time at feeder club Tweed Heads after being unable to break into the first team.
“We are really pleased to have secured a permanent deal with Joe and he fully deserves this contract. He has trained well and done everything asked of him,” Rhinos boss Brian McDermott added.
“He has been very professional since he joined and we were impressed with how he went against Wakefield on Boxing Day and he made a good start to his Leeds career with two tries.”
Elsewhere, former St Helens legend Paul Sculthorpe has been named in the Queen’s New Year Honours List, and he will receive an MBE after services to the game and charity.
“Big thanks to everyone for their congrats on the MBE…can tell you everything during my career and after has been a pleasure! #RL & #Charity,” he posted on his Twitter account.