The win lifts Canberra back to third spot on the ladder, ramping up expectations of a title push while the Storm remain in first with three games remaining in the regular season.
Canberra stunned the visitors with a try in the first set of the match, Leilua putting Blake Austin into the backfield before backing up to score the quickest try of the season.
Storm halfback Cooper Cronk replied when he ran the ball in the 17th minute, however Leilua returned by ploughing through three defenders seven minutes later.
Jarrod Croker's penalty goal gave Canberra a six-point advantage at halftime before Shannon Boyd crashed through under the posts in the 54th minute and Croker sealed the win with a 76th minute penalty goal.
Leilua retired late in the game with what appeared to be a bad cut to his leg.
Hooker Josh Hodgson could find himself in trouble for a possible grapple tackle in the first half.
- AAP