What makes the victory all the sweeter for O'Neill is that his father, Henry, ran unsuccessfully for mayor against Jensen 16 years ago.
"I'm very happy as far as my heritage goes because I'm continuing the family tradition," said O'Neill, whose father died three years ago. "My family has always been active in Jenkintown politics since we came here in the 1860s. My father was a councilman. I had an uncle who was a Democratic committeeman and I'm proud to carry it on."
O'Neill wasn't the only Jenkintown resident who was surprised by the commanding victory, which will make him the first Democratic mayor in borough history when he takes office in January.
Gary Hutnick, chairman of the Jenkintown Regular Republican Organization, said he and other GOP leaders were caught off-guard by O'Neill's win.
"Some people in predominantly Republican wards voted Democratic, and maybe Ted (Jensen) was not as visible as he should have been," Hutnick said. ''Michael, when I talked to him before the election, told me he had been out every Sunday knocking on doors. The Republicans didn't do that."
Jensen, who has served as Jenkintown's mayor for 16 years, attributed his defeat to complacency on the part of the Republicans - and O'Neill's hard work.
"Frankly, I think a lot of the Republicans didn't come out to vote. Michael (O'Neill) knocked on a lot of doors, and maybe we've become a little lethargic. A lot of people told me afterward, 'Oh, if only we'd known (of O'Neill's strength as a candidate) we would have voted," Jensen said.
O'Neill, who operates a beer distributorship, said he does not think his victory indicates voters' dissatisfaction with Jensen or the Republican- dominated Jenkintown Borough Council.
"I knew I had to hit every door in town, and every Sunday I went door-to- door saying hello and giving my card out. The only ward I lost was the Second Ward, which includes the Beaver Hill condominium. I wasn't allowed to canvass there, and I think that indicates the importance of personal contact."
In Jenkintown, the mayor serves as the borough's ceremonial leader and as a liaison between the Police Department and residents. The mayor also casts the tie-breaking vote at meetings of the Borough Council.
Noting that Jensen has been active in borough politics for about 40 years and frequently has served as a mediator for the often-divided Borough Council, Hutnick said he thought O'Neill would find it difficult to fill the incumbent mayor's shoes.
But O'Neill said he would try to compensate for his inexperience with the same hard work with which he won the election.
"I feel I have an especially large responsibility to do a good job because I'm the first Democratic mayor," O'Neill said. "I know people will be watching me closely."