Christopher Massimine, whose job as the managing director of the Pioneer Theater Company in Salt Lake City was thrown into doubt after a local television affiliate found that he had embellished his résumé with untrue claims, announced Monday that he would resign his post and said that he had long struggled with mental illness.

Massimine announced his resignation shortly after The New York Times published an article about his career, and the discrepancies and errors on the résumé that had helped him win the position at the Pioneer, the largest professional theater company in Salt Lake City.

“Despite many good things that have happened over the last two years under my direction, effective Aug. 20, 2021, I will resign my position at Pioneer Theater Company in order to address issues in my personal and professional life, stemming from untreated and at times an incorrectly treated mental health condition,” he said in a statement.

Massimine, who said that he had battled with mental illness for his entire life, and that most of his friends and colleagues had not known of his condition, had come to the Pioneer Theater from the National Yiddish Theater Folksbiene in New York.

Massimine was something of an unusual choice to lead the Folksbiene, a small nonprofit with a niche audience.

In 2012, when he became an executive with the century-old theater that produces shows for a largely older audience, he was a 26-year-old Italian American Catholic with limited experience as a theatrical administrator and even less with Yiddish.

But when he left seven years later, the Folksbiene’s “Fiddler on the Roof,” directed by Joel Grey, was moving from its own theater, within the Museum of Jewish Heritage, to Stage 42, one of Off Broadway’s largest venues. The show had already enjoyed a sold-out run at the museum, and the theater’s revenue had more than doubled in a year to nearly $5 million.

“He was smart, dedicated, motivated, professional and always a pleasure to deal with,” said Ron Lasko, a publicist who worked with Massimine at the Folksbiene.

To the surprise of many, though, Massimine did not stick around to celebrate the successful transfer of “Fiddler” to a new theater. He instead left the Folksbiene in early 2019 and soon accepted a job as the managing director of the Pioneer Theater Company.

“Chris has a proven track record of success,” Dan Reed, a vice president with the University of Utah, which oversees the professional theater on its campus, said at the time of Massimine’s appointment.

But two years into his tenure there, Massimine was accused of embellishing his life story with wildly inaccurate depictions of his theatrical pursuits and side gigs.

Working from public records and tips, Salt Lake City’s Fox affiliate KSTU-TV reported earlier this year that Massimine did not have a master’s degree from New York University, as asserted on his résumé. The station said his claims to have helped develop popular video games and some major advertising campaigns did not check out.

And, though he said he had received a national arts advocacy award — and released a picture of himself wearing the medal — the bestowing organization does not appear to exist.

Adam Herbets, a reporter for the television station, said his sources included people who had seen Massimine’s résumé and found it “unbelievable.”

“And, you know,” he continued, “unbelievable sometimes has a positive connotation and sometimes has a negative connotation. In this case it’s literally not believable.”

Massimine, whose representatives had denied some of the accusations that he had misrepresented his accomplishments, acknowledged Monday night that there had been “errors” in his résumé.

“Local and national news outlets have reported this year that I misrepresented my work history on my résumé, in press releases and interviews, both prior to accepting the P.T.C. position and during my tenure here,” he said in the statement. “There is a fair amount of truth within the reporting, withstanding discrepancies. Regardless, I take responsibility for errors in my résumé but stand by my work product throughout my career.”

As it turns out, Massimine’s embellishments extended beyond what the TV station had reported, to include claims that he was born in Italy and was once a full-time employee of the Dramatists Guild.

Before the resignation, Chris Nelson, the Utah university’s director of communications, had acknowledged that some “misinformation” had been found on Massimine’s résumé and that his position was put “under review.”

In prior remarks, his wife, Maggie Massimine, had said that her husband was on family medical leave and not available for interviews. A spokesman for Massimine, Michael Deaver, had said that some of the discrepancies might have been attributable to misunderstandings on matters such as his client’s work on ad campaigns, where he had been employed by a subcontractor.

Maggie Massimine had denied that her husband had exaggerated or misled people, but she did not directly discuss his mental state and said she could not address some of the discrepancies.

“Our side of the story has not been told,” she said in an interview several weeks ago. “I really wish I could say more.”

At N.Y.U., Massimine earned a bachelor’s degree in dramatic literature in 2007, a university spokesman said, after three years of study. Maggie Massimine said her husband thought he had earned both a master’s and a bachelor’s degree, until KSTU reported he had not. “He was as surprised as everyone else,” she said.

Massimine’s profile on LinkedIn, the professional networking site, reports that during his college years he also served for more than 18 months as “publications manager and creative affairs coordinator” for the Dramatists Guild, a service organization for playwrights.

However, Tari Stratton, director of education for the guild, said it seems Massimine spent only four months there as an unpaid intern. “We do not have any records indicating Mr. Massimine held any paid positions with the guild or had any title other than intern,” she wrote in an email.

Massimine did serve in a number of roles with theatrical organizations before joining the staff of the Flea, a small, scrappy New York theater, in 2011. The following year he was hired by the Folksbiene and was promoted to chief executive in 2016.

At the Yiddish theater, framed letters from Hal Prince, the legendary Broadway producer and director, hung in Massimine’s office. He counted Manny Azenberg, a producer and eight-time Tony Award winner, among his mentors, and appeared poised to continue advancing through the ranks of Manhattan’s theater ecosystem.

Bruce Cohen, a retired publicist who worked with the Folksbiene to promote its Drama Desk-nominated operetta “The Golden Bride,” said Massimine was “a very sweet man” capable of deftly navigating tempestuous artist egos.

Beck Lee, who served as a publicist for the Folksbiene during much of Massimine’s tenure, described him as an ambitious hard worker.

“He did a great deal to raise the profile of the company,” Lee said, “and was sometimes prone to exaggeration, which I have learned is typically a tool of impresarios and showmen. If anything I thought he was a 21st-century version of a David Merrick, happily pushing his shows to the public and the press with bluster.”

Certainly there were issues with a 2018 profile of Massimine that ran in The Daily Beast under the headline, “Meet Christopher Massimine, the ‘Nice Goy’ Running the National Yiddish Theatre.”

The piece, based on an interview with Massimine, reported he had come to the United States as an infant from Italy and had appeared on Broadway as a child in shows like “Beauty and the Beast” and “Les Misérables.” But he was born in New Jersey and there are no records of him performing in either show, according to the Broadway League’s database, which is widely viewed as authoritative.

Despite his success in leading the Folksbiene, the circumstances under which Massimine left the theater are not clear, and its executive director declined to comment. Beck Lee, the former publicist for the theater, said that he was told by theater officials that Massimine was asked to leave after having invested theater funds in an unrelated production without authorization.

“He was given the opportunity to admit his behavior, and leave without further incident,” Lee said.

A second person with knowledge of the dispute agreed that Massimine had left after an issue over an investment.

But Maggie Massimine denied there had been any problem like that, and noted that her husband had been invited back to attend the opening of “Fiddler” at Stage 42 in February 2019.

In Utah, Massimine was hired at a salary of $152,000 to run a theater with nearly a $5 million operating budget. The school had paid a search firm, Management Consultants for the Arts, nearly $36,000 to recommend candidates.

“That résumé was so extraordinary that it probably intoxicated people,” said Brant Pope, chair of the drama department at the University of Texas at Austin and past president of the University Resident Theater Association. “It probably blurred their vision.”

Maggie Massimine said her husband had heard of the Utah job through his relationship with Azenberg, the producer who has been an influential backer of the Yiddish theater. Azenberg’s daughter, Karen, a former Broadway stage manager, has served as the artistic director of the Pioneer Theater since 2012.

“The search committee was looking for a managing director who would help this theater grow and would support my desire to develop new musicals,” Karen Azenberg wrote in an email.

In Utah, Massimine continued to promote his own accomplishments. Two years ago, using information he provided, his new theater put out a news release stating he had been named “Humanitarian of the Year” by the National Performing Arts Action Association and would be honored at a reception in Washington.

Jenny Thomas, a spokesman for the Association of Performing Arts Professionals, a Washington-based advocacy group, said that neither she nor several other colleagues who work for similar nonprofits have heard of the National Performing Arts Action Association.

No organization by that name has a website or is mentioned by news outlets aside from those that picked up the news release from the theater.

But Massimine traveled to Washington in January 2020, purportedly to pick up the award, and later billed the university nearly $800 for his expenses. An image of him on the trip, supposedly taken at the White House and wearing a medal, was credited to the fictitious National Performing Arts Action Association and appeared two months later on a website with an article about Massimine’s relationship with his mother.

The writer of the piece said the photograph, caption and credit information were provided by Massimine.

Joseph Berger contributed reporting.