The former Dundee United player has impressed since joining on a short-term deal in January.
Irish midfielder Sammy Stewart, 17, has joined from Irish outfit Glenavon, also on a two-year contract.
And director of football Willie Miller is hopeful full-back Alan Maybury will stay on after his January switch from Leicester.
"We would be delighted to keep Alan," said Miller. "I have had long conversations with him. He seems to have enjoyed his time at Aberdeen.
"He has been playing at a high level and a high level financially, that we cannot compete with, but we hope to compete in football terms."