As Pete Buttigieg makes his final push for votes ahead of Monday’s Iowa caucus, his army of volunteer door knockers will include a retired South Bend, Indiana, businessman and political powerbroker who is also making his debut on the national stage.

Bob Urbanski, a local contractor and longtime Democratic donor in Indiana, has quietly served as a key behind-the-scenes figure in Buttigieg’s political career, offering early support, crucial connections and the tens of thousands of dollars needed to finance his meteoric rise from mayor of a modest-sized city to legitimate contender for the Democratic nomination for President of the United States.

Campaign finance records reviewed by ABC News suggest that Urbanski was Mayor Pete’s most prolific early backer. His name might not be familiar outside of the Rust Belt, but in South Bend, his word -- and his wallet -- carry weight.

"He’s not the face of the party. That’d be the [Democratic] chair or party official," South Bend Common Councilman Jake Teshka told ABC News. "But he’s the one calling the shots. He’s the kingmaker."

Though he rarely gives interviews, Urbanski spoke at length with ABC News, about his own career and his relationship with the recent Harvard graduate who, after a stint with the McKinsey & Co. consulting firm, returned home with a desire to enter politics.

"The first meeting I had with him lasted three hours," Urbanski told ABC News. "I was awed."

The son of Polish immigrants, Urbanksi grew up in a South Bend booming with industry. His father was a butcher and Democratic precinct committeeman, and Urbanski remembers the book his father kept in his bedroom in which he wrote the names and personal details of every member of his precinct. Urbanski soon followed his father’s lead, telling ABC News he first got involved in local Democratic politics in the 1970s.

He would enjoy a successful career focused largely on growing Indiana’s roads and infrastructure. He started working at Morse Electric -- a company that worked on the Indiana Toll Road -- and later helped launch a firm called Trans Tech Electric, which grew into one of the state’s top electrical contracting firms. In the 1990s, he joined the board of the South Bend lender Sobieski Bancorp Inc., going on to become chairman of the bank from 2002 to 2013.

Meanwhile, Urbanski became a regular supporter of Democratic candidates and causes. He backed the bids of two South Bend natives for statewide office and gave tens of thousands of dollars to the state party committee, in addition to serving as campaign chairman for three candidates for South Bend sheriff, and one candidate for county commissioner.

One longtime South Bend resident involved in politics -- who spoke to ABC News on the condition of anonymity -- said Urbanski’s local power is pervasive.

"[Urbanski] had run Trans Tech Electric for decades and they had an enormous amount of contracts with the city and he just built up a rapport with city leaders,” the resident said. “[He has] basically been calling the shots, as it were, for 40 years.”

It was early summer in 2009, Urbanski recalled, when the phone rang, and a young man with a hard-to-pronounce name on the other end of the line told him he was contemplating a bid for Indiana state treasurer and asked if they could meet for lunch.

Unlike a "typical politician," Urbanski said, Buttigieg arrived at the meeting with a surprisingly deep understanding of problems facing the state and sophisticated ideas about how to solve them. He set up another meeting with Buttigieg a week later "to give him a check," he said, and to offer some frank advice.

"I basically told him, 'Look, you're going to lose this state treasurer's race.' And he said, 'Well, that's not very nice.'" Urbanski told ABC News. "And I said, 'Well, nobody can win it in this Republican state in an off-year. … I said, 'Quit this race, get the hell out of it, and let's start running you for mayor.'"

Buttigieg was flattered, Urbanksi said, but told him he was already committed to the treasurer’s race, having amassed too much support to let his backers down.

Buttigieg lost the state treasurer’s race by 20 points. After the votes were tallied, Urbanski said his phone rang again. "He said, 'You got your wish, I lost.'"

It wasn’t long before Urbanksi signed on to be Buttigieg’s campaign chairman for his next run -- for mayor.

Urbanski’s support was critical to Buttigieg’s initial victory as well as his reelection bid. He donated money, office space,and even his home for high-dollar fundraising events, according to available campaign finance records for both races.

The full scope of his financial contribution is unclear. St. Joseph County officials told ABC News their record retention schedule doesn’t require the clerk’s office to preserve all campaign finance records, making it difficult to determine the total amount of contributions from Urbanski to Buttigieg over the years.

But available campaign finance reports reviewed by ABC News show that Urbanski continued to write checks to Buttigieg’s mayoral committee through 2018, donating at least $43,000 to his local and state political accounts.

Urbanski said he never sought political favors or benefited personally from the close relationship he established with Buttigieg. Urbanski told ABC News that his contracting operations did substantial business with the city during the years predating Buttigieg’s tenure as mayor -- but that work had largely ended by the early 2000s, before Buttigieg took office.

Urbanski was tied, however, to one of the characters in a long-running controversy inside the South Bend Police Department-- an issue that has followed Buttigieg beyond South Bend.

In 2006, during a dispute with a South Bend construction contractor, Urbanski dispatched an off-duty police officer to the job site. The officer -- Tim Corbett -- allegedly approached the contractor with his badge and gun in view and told the man "he needed to comply with Mr. Urbanski's demands, or he would go to jail," the contractor alleged in a lawsuit against Urbanski, Corbett and others. Ultimately, the lawsuit was dismissed upon appeal.

Corbett, who received a one-day suspension over the incident, told ABC News he considers the matter "in the past," and said, "I don't think of them anymore." For his part, Urbanski denied any wrongdoing but acknowledged that he asked Corbett to go over to see the contractor and "I wasn’t there with Tim to know what he did."

That episode received renewed attention when, years later, Corbett’s name resurfaced during a legal dispute over surreptitious recordings of members of the South Bend Police Department that were said to capture officers using racist language. The tapes have not been released, but Corbett is one of the officers believed to have been recorded, and he and a group of other officers are fighting to keep them from reaching the public.

Dr. Oliver Davis, a former South Bend council member who is backing a Buttigieg opponent in the 2020 presidential contest, said Buttigieg's handling of the controversy ultimately reflected poorly on his "style of leadership."

In 2018, as that controversy continued, Urbanski backed Corbett’s failed bid at county sheriff. Urbanski told ABC News on several occasions, saying that he believes there’s "no better cop" than Corbett.

"Unfortunately," Corbett told ABC News, "Bob and others around me have been painted with a broad brush."

As Buttigieg’s star has risen, Urbanski’s support has continued.

Urbanski was among the first donors to give Buttigieg’s campaign the maximum allowable amount when he made the leap into the crowded 2020 Democratic primary field, writing a $2,700 check last year, according to federal election filings.

But as Buttigieg’s popularity has grown, so has his roster of large-dollar donors. According to the Center for Responsive Politics, his campaign has raised more than $27 million from large-dollar donors, including at lavish events in Hollywood that attracted the ire of his opponents.

Urbanski’s money might be less critical to Buttigieg’s presidential campaign than his shoe leather. With the Iowa Caucus just days away, Urbanski is on the ground in Iowa, talking to potential voters about the young politician who captivated him 11 years ago.

He told ABC News he is prepared to "do anything [the campaign] tells me might be of value." On his docket: Visits to diners and coffee shops to "engage with people and tell them about Pete." His real value to Buttigieg now, he said, is that he can speak about the candidate based on his own personal experience.

"He doesn't run his mouth until he thinks about what he's going to talk about and makes sure he understands it," Urbanski told ABC News. "I’ve seen that here [in South Bend]."