President Biden delivered an anecdote to union workers at a Harris-Walz campaign event in Pennsylvania, saying that his great-grandfather was accused of being a member of a violent Irish secret society, in what social media commenters called an "insanely weird story." 

"I remember when my great-grandfather was only the second Catholic elected statewide in the state Senate here in Pennsylvania," Biden told Harris-Walz supporters on Labor Day at a union hall in Pittsburgh. "And I remember they talked about — when they’d run against him in 1906 — they said, ‘Guess what? He’s a Molly Maguire.’"

The Molly Maguires were an Irish secret society that operated in Ireland, parts of England and in Biden's homestate of Pennsylvania. In the Keystone State, they were known as a band of Irish immigrants who would attack, and sometimes allegedly murder, anti-Irish Catholic mine owners. 

"A lot of the English owned the coal mines," Biden said. "And what they did was they really beat the hell out of the mostly Catholic population in the mines. Not a joke."

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President Biden speaks during a campaign event for Democratic presidential nominee Vice President Kamala at IBEW Local Union #5 on Sept. 2, 2024 in Pittsburgh. (Photo by Michael M. Santiago/Getty Images)

Biden went on to explain how the Molly Maguires would defend Catholic immigrants targeted by Protestant mine owners and foremen. 

"And Molly Maguires, if they found out the foreman was taking advantage of an individual, they would literally kill him. Not a joke. And they would bring his body up and put him on the doorstep of his family," he said. 

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"Kind of crude, but I gotta admit they accused my great-grandfather of being a Molly Maguire — he wasn’t, but we were so damn disappointed," Biden quipped, sparking laughter from the union workers.

"That was a joke. That was a joke," Biden then said to the crowd. 

The Molly Maguires have an infamous and debated history in Pennsylvania, which included the 1877 execution of six men allegedly involved with the secret society in Pennsylvania. 

Social media commenters said the anecdote was an "insanely weird story" on X, while others accused the president of repeating a "tall tale."

Fox News Digital reached out to the White House regarding social media claims that it was unlikely the great-grandfather was suspected to be a member of the secret society as he would have been a teenager during the Molly Maguires' hey-day in Pennsylvania. The White House directed Fox News Digital to an Irish America Magazine article that previously reported on Biden's great-grandfather and his ties to Pennsylvania and the Molly Maguires. 

An illustration depicts Frank McAndrew, driving a sleigh, alerting his passenger McKenna (Pinkerton detective James McParlan) that they are being followed by a man who aims to take his life in Pennsylvania in the late 19th century. (Photo by Interim Archives/Getty Images)

The publication Irish America reported in 2020 that Biden’s great-grandfather, Edward Francis Blewitt, had deep roots set in Biden’s hometown of Scranton, Pennsylvania, at the turn of the century. Blewitt served as chairman of the Saint Patrick’s Day Parade in 1897, was elected to the state senate in 1906 and co-founded the Friendly Sons of St. Patrick in Scranton in 1908.

The article detailed that Biden's great-great-grandfather James Finnegan moved to Scranton, home to the Molly Maguires, and that his son was rumored to be a member of the secret society. 

"Rumored to be a member of the Molly Maguires was Biden’s great-grandfather Edward Francis Blewitt, a native of Louisiana whose parents Patrick and Catherine (nee Scanlon) Blewitt were from Ballina, Co Mayo." it continued. 

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Biden has also previously cited his grand-grandfather while on the campaign trail, including in 2008 when he was running as then-Sen. Barack Obama’s presidential running mate.

An illustration depicts the trial of alleged Molly Maguire members John Kehoe, Michael O'Brien, Chris Donnelly, John Donahue, James Roarty, Dennis Canning, Frank McHugh, John Gibbons, and John Morris for conspiracy of murder in Pottsville, Pennsylvania, in 1876. (Photo by Interim Archives/Getty Images)

"I hope you won’t hold it against me, but I am a hard-coal miner, anthracite coal, Scranton, Pa.," he said in 2008 in Virginia.  

"It’s nice to be back in coal country. … It’s a different accent [in Southwest Virginia] … but it’s the same deal. We were taught that our faith and our family was the only really important thing, and our faith and our family informed everything we did."

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President Biden speaks during a campaign event for Democratic presidential nominee Vice President Kamala Harris at IBEW Local Union #5 on Sept. 2, 2024 in Pittsburgh. (Photo by Michael M. Santiago/Getty Images)

He added of his great-grandfather’s alleged connection to the Molly Maguires, "He went out of his way to prove that he wasn’t, and we were all praying that he was."

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Biden dropped out of the presidential race in July, as concerns mounted around his mental acuity and traditional Democratic allies in Congress and in the media called on him to step aside for another candidate. Biden endorsed Vice President Kamala Harris shortly after bowing out of the race, catapulting her to the top of the ticket. Harris became the Democratic Party’s official nominee last month in Chicago during the DNC. 

Biden's appearance on Monday in Pittsburgh marked the first time he hit the campaign trail in support of Harris since dropping out. 

Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.