Republican presidential candidate Donald Trump, right, shakes hands with co-headliner Jerry Falwell Jr., leader of the nation’s largest Christian university, during a campaign event at the Orpheum Theatre in Sioux City, Iowa, on Jan. 31. (Dave Kaup/Reuters)

This post has been updated. 

DAVENPORT, Iowa -- As Liberty University President Jerry Falwell Jr. took the stage at a campaign rally for Donald Trump in eastern Iowa on Saturday night, the announcer introduced him as a reverend.

"First of all, I'm not a reverend," Falwell said. "I have to make that correction everywhere. I'm a college president. I've spent ... all of my adult life trying to make Liberty University a world-class Christian university."

Falwell says his endorsement of Trump  this month was a personal one, not a professional one, as tax-exempt institutions like universities and churches are not allowed to make political endorsements. But talk of Liberty dominated the event that night, along with two more in western Iowa on Sunday, as Falwell urged evangelical caucus-goers to pick Trump.

In introducing Trump in Davenport on Saturday, Falwell recounted how Liberty struggled in its early days, forcing him and his late father to beg for donations and loans to cover their payroll. Now, Falwell said the university is the largest of its kind and prosperous.

"That's really one of the things that attracted me to Donald Trump is that I see our country at a stage now where we're approaching $20 trillion in debt, and it reminds me of where Liberty University was in the 1990s, when we were struggling to survive," Falwell said. "And it just convinced me that we need a businessman.... We need somebody besides a career politician, somebody who has been in the real world."

Falwell said he's proud to endorse Trump, who then joined him on stage. Falwell kept talking about his university and comparing it to Trump: Falwell said Liberty is financially stable and has not allowed big donors to dictate changes to the school's core beliefs and mission, which Falwell compared to Trump rejecting super PAC money. Falwell said his father was overly generous and gave out scholarships even when the school was close to declaring bankruptcy, which he compared to Trump recently donating $1 million to organizations that help veterans. Falwell said he encourages his students to carry concealed weapons on campus, which he compared to Trump saying he wants to get rid of gun-free zones and protect the rights of gun owners.

"The job that Jerry has done at Liberty University is amazing," Trump said, adding that he has reviewed the school's finances. "You're one of the most financially solid, financially sound universities in the entire United States, with a tremendous endowment and tremendous amounts of money that can go for expansion. You don't have debt. You've done an amazing job."

It was then, more than 10 minutes into Falwell's time on stage, that the college president added a disclaimer to his endorsement.

"That's why I have to make it clear that it's not Liberty's endorsement, it's my personal endorsement, because the IRS would love to get their hands on that, too," Falwell said, referring to his school's money, as Trump laughed.

Falwell said in an interview that since Saturday night, he has learned to make that disclaimer sooner and more forcefully in his comments. He said his staff has told him that as long as he makes clear to audiences he is endorsing Trump as a private citizen, not a college president, he can share anything he wants about his life story and years at Liberty.

"I believe we all have the right as private citizens to endorse candidates and participate in the political process," Falwell said in an interview on Monday afternoon, adding that his years at the college have helped to form his personal views. "It's almost impossible to explain to somebody my view of the world without relating personal stories."

The Falwell name is deeply intertwined with Liberty's identity. Falwell's late father, the televangelist Jerry Falwell, founded the school in 1971. When asked about how Falwell separates his personal identity from his professional one, a Liberty University representative responded with a statement: "Liberty University does not support or oppose candidates for public office." The Trump campaign has repeatedly said Falwell's endorsement is a personal one.

Politicians frequently visit Liberty's campus in Lynchburg, Va., and Sen. Ted Cruz (R-Tex.) launched his presidential campaign there. Although most political visitors are Republican, Liberty recently hosted a Democratic candidate for president, Sen. Bernie Sanders (I-Vt.).

Trump spoke at liberty on Jan. 18 during one of the school's three weekly convocations, highly produced worship services that students are required to attend. As Falwell introduced Trump that day, he said: “As you know, Liberty University does not support or oppose candidates for public office, and Mr. Trump's appearance here should not be interpreted by any as an endorsement by Liberty."

About a  week later, Falwell personally endorsed Trump. The decision was at first questioned by others in the evangelical community, Falwell said in an interview. But he said that once he explained his reasons in a post on his personal Facebook page, the complaints ceased.

Other evangelical leaders have stopped short of formally endorsing Trump because they lead tax-exempt organizations. The Rev. Robert Jeffress, who leads the 12,000-member First Baptist Dallas, spoke at a Trump rally in Sioux Center in western Iowa on Jan. 23 and made clear that while he cannot "officially endorse a candidate," he would not be in Iowa if he were not "absolutely convinced that Donald Trump would make a great president."

Falwell joined the Republican front-runner this weekend on the campaign trail in Iowa, where evangelical voters play a major role in the caucuses. Falwell told a crowd in Sioux City on Sunday night that Trump served Wendy's cheeseburgers on his private jet, making him feel right at home. Three times over the weekend, Trump had Falwell interview him on stage, fireside-chat style, allowing the school leader to do the most talking -- and promote his university to thousands of Iowans.

At one point during the event in Davenport on Saturday night, Falwell reflected on the "numerous" politicians who have visited his university and why he felt compelled to endorse Trump.

"It's unusual for a college president to endorse," Falwell said. "But I just see our country at such a critical crossroads, and I think we need business leadership. I think we're at the point where we've tried lawyers, we've tried the career politicians. We need a businessman."