The Secret Service reportedly is being accused of leaking private information on how Republican Rep. Jason Chaffetz -- one of the agency's toughest critics -- was rejected for a job there more than a decade ago. 

The bizarre chain of events prompted Homeland Security Secretary Jeh Johnson to personally call Chaffetz on Thursday night and apologize. Secret Service Director Joseph Clancy also called to apologize, according to a DHS spokeswoman. 

Spokeswoman Marsha Catron said in a statement that Johnson is now seeking an investigation, "and if the allegations ... are true, those responsible should be held accountable." 

She said Johnson apologized to Chaffetz "for being put in the situation that he had to acknowledge a matter that should have been kept confidential." 

The Utah congressman, as chairman of the House Oversight and Government Reform Committee, has been relentless in his scrutiny of the agency, particularly in the wake of a March incident where agents returning from a party drove into an active bomb investigation scene. Chaffetz earlier this week subpoenaed the two agents in question -- a step Johnson called "unprecedented and unnecessary." 

But The Washington Post later reported that senior staffers on Chaffetz' committee received whistleblower allegations that Secret Service staff were circulating potentially embarrassing information about the congressman. 

Indeed, the Daily Beast reported shortly before the Post article was published on his job application. The Daily Beast reported that Chaffetz applied for a Secret Service job around 2003 and was rejected, something he hadn't disclosed before. Chaffetz told The Daily Beast he was turned away, he thought, "because I was too old." 

Chaffetz told the Post it was "disconcerting" to learn agency workers might have been circulating this information. 

"I won't be intimidated, but I'm sure that's what it's intended to do," he said. 

Even before Johnson called for an investigation, Chaffetz' committee reportedly forwarded the whistleblower allegations to the DHS inspector general for possible investigation. 

In a statement on Friday, Secret Service Director Clancy vowed that "any allegations concerning potential privacy violations will be thoroughly investigated," and anyone found to have violated policies "will be held accountable and face appropriate administrative action." 

Chaffetz would hardly have been alone in being rejected from the Secret Service. According to Bloomberg, the agency is one of the most difficult law enforcement agencies to join -- in 2011, fewer than 1 percent of the thousands of special-agent applicants were hired. 

The apparent leak of Chaffetz' job application history marks another clash in the chairman's interactions with the agency. 

Late last month, Chaffetz held a hearing where he confronted the Secret Service director over the incident outside the White House -- complaining not just about the two agents who drove through the scene but the handling of the suspicious package threat. He played surveillance footage from that night, alleging it took far too long to secure the scene after a woman dropped off what she claimed was the bomb (which turned out to be a book). 

"We expect answers," Chaffetz said at the time. 

FoxNews.com's Judson Berger contributed to this report.