Had Republican Michael Ping been able to knock off incumbent Democrat Mike Compton in District 5 — Ping lost by 51 votes — the GOP would have taken control of the council.
As it stands, Democrats still hold a 5-4 majority heading into the next four years.
"I’m not disheartened, I’m not disappointed," Ping said by phone from his home late Tuesday. "I'm very proud of the showing I had."
Despite the close margin, he said he has no plans at this point to ask for a recount.
"I think what we’re going to do is we’ll review the results, see what the absentee count was and what the precinct count was, and then take it from there," he said.
"I tell you what, I'm thrilled," Republican John Reisdorf, who unseated Democrat Ross Deal in District 3, said from inside the ballroom at Riverside Terrace in Mishawaka, where GOP candidates and supporters had gathered Tuesday to celebrate.
"I'm pretty excited, I'm pretty excited," said Dan Bilancio, the other new GOP member on the council. "It's a real privilege and honor to be chosen by the voters."
Voters elected Bilancio and Democrats Matt Mammolenti and John Roggeman to at-large seats on the council over Gleissner and Republicans Paul Saros and Josh Holt. Less than 5 percentage points separated the six candidates.
Gleissner, seeking his seventh consecutive term on the council, finished fifth in the race but only 157 votes out of the top three.
"I'm saddened. It brings a long career to an end," the 68-year-old former school teacher said by phone from his home late Tuesday.
"I guess I just regret not having worked as hard as I probably could have," he said. "I sat outside tonight — I had a little firepit — throwing away some campaign information I didn't get out and thinking why I didn't."
"I'm just sad for John," Roggeman said from inside De Amicis Club in Mishawaka, the designated Democratic hangout Tuesday. "He devoted a lot of his life to Mishawaka ... and he will be missed."
"A lot of good candidates lost," said Mammolenti, a winner Tuesday in his first campaign for political office.
According to Ron Banicki, the ballot petition scandal involving the county Democratic Party and negative campaigning on the part of the state Democratic Party likely turned some Mishawaka voters against Democratic candidates.
Banicki, an incumbent Democrat, defeated Republican Jim Pingel by 60 votes in District 6.
"That was two strikes," he said, "so I felt like we were fighting an uphill battle."
On the Republican side, Bilancio credited the party for bringing the entire crop of GOP candidates together as a team under a banner of integrity and fiscal responsibility.
"We've been together from the very beginning," he said, "and I think we'll remain that way."
In other Mishawaka Common Council races Tuesday: