The lanky Victorian took the title, his second Australian PGA Legends Tour win in the past fortnight, after the final round at the Kingston Beach Golf Club was washed out by heavy rain.
Harwood shot a blemish free six under 65 in the first round and that was more than enough to claim the title when the second round was abandoned after six holes.
He had started the final round two ahead of fellow Victorian David Good who finished outright second after his 4-under 67.
South Australian Garry Merrick (69) and Mike Zilko (NSW) (70) were the only other players to break par in what were tough conditions in the opening round with 30 plus degree temperatures and a stiffening sea breeze.
The win means Harwood is the only player to ever win the Tasmanian Senior Open three times and comes on top of his win at the NSW Legends Championship at the Oatlands Golf Club early last week.
“It is a great honour to win the event for a third time,” Harwood said after accepting the title. “The course was presented beautifully and whilst it is disappointing to not be able to finish the round today, I am more than happy to take the win,”
“I will be heading to the European Seniors Tour again this year and it gives me great confidence to have now had a couple of wins before the season starts in Europe.”
Other notables in the field were Rodger Davis who finished in a five way tie for fifth on even par while 1990 US PGA Champion Wayne Grady was a further three shots back in a tie for 14th.
Graham Roberts from Royal Hobart Golf Club won the best gross score for the amateurs with Queenslander Eric Oxenford taking out the best nett score.