Shortland, who will turn 23 later this month, will play for Taieri as a midfield back, and says he wants to go as far as possible in the game.
He has not signed a contract but the club has arranged a job for him, working with youth, and Shortland said he couldn't wait to get involved.
"I wanted to stay in New Zealand and I have lived in Auckland and checked out Christchurch, and I thought I would like to live down here, and have a good look around," he said.
"The first goal is to have a good season for Taieri and go from there. Obviously I'd like to play for Otago but I'll just take it one step at a time."
He has not signed a contract with Otago.
Taieri is back in the premier grade this season after withdrawing in 2000.
Shortland does not have a rugby background, but said he had already started analysing the game, and hoped to pick up a few tips from his new team-mates.
He played a game for a New Zealand Invitational team against the All Blacks in October last year, before the Grand Slam tour.
Shortland was born in Masterton but moved to Sydney when he was 2 and started playing rugby league at school.
He made an Australian Institute of Sport side in his teens and then linked up with the Melbourne Storm side.
He played two years for the Storm feeder side, Brisbane Norths, and then had two injury-affected years with the Storm, making just one appearance for the NRL side before leaving for the Warriors at the end of 2007.
He played five games for the Warriors last year but with his path blocked by international centres Jerome Ropati and Brent Tate, and the club signing a couple of outside backs for next season, he had to look elsewhere.
"That is what the NRL is like now. If you haven't cracked first grade by the time you're 21 or 22, then the clubs look elsewhere," he said.
Shortland said there had been interest from the Auckland union and the Queensland Reds, and also the chance to go to a French club but he had made contact with an Otago rugby connection, and Taieri had got involved.
He said the biggest difference between the two codes was the ruck.
Taieri premier coach John Kelly said it was great to have procured the services of Shortland and he hoped the former league player would bring a professional approach to the club.
The club was hoping to attract more players, especially Taieri-based players who had played for town clubs in past years.