He portrays a charming, charismatic ad creative with a dark, hidden history in the television show Mad Men. Now it’s been revealed that actor Jon Hamm may have a shady past of his own.

Jon was a member of the now-disbanded Sigma Nu fraternity at the University of Texas in Austin when he helped forcefully initiate a male student in 1990 and was charged with hazing.

The event occurred when Hamm was a second-year student in Austin, Texas, according to court and school documents obtained by Star magazine this week. The victim was Mark Sanders, a Sigma Nu “pledge,” as students who join a fraternity are called. Mr Sanders, then 20 years old, said he was subjected to a long, brutal ritual that involved being carried around the frat house with a hammer and having his pants lit on fire.

The suit said Hamm cooperated “till the very end” in the 1991 case.

Although the actor was charged with hazing, he was not found guilty. According to the Associated Press, he was given “deferred adjudication,” which permits a case to be dropped if the offender successfully completes probation.

Although none of the documents were sealed, Hamm was not well-known at the time of the occurrence, and his involvement in the case was not revealed until Star magazine published an article about it this week.

Mr Sanders was unable to recite a list of details he was supposed to have memorized about members of the fraternity, according to a 1991 lawsuit. Hamm became “mad, I mean really mad”. Mr Sanders said, “He rears back and hits me left-handed, and he hit me right over my right kidney, I mean square over it. Good solid hit and that, that stood me right up.”

Hamm and his fraternity brothers then reportedly hoisted Mr Sanders into the air by his underpants and “pulled it back and forth in a sawing motion,” before setting fire to the pledge’s trousers, telling him he couldn’t put out the fire with his hand and had to “blow it out.” Mr Sanders was beaten with a paddle and taken “around the fraternity house with the claw of a hammer beneath his genitals,” according to a 1991 account in The San Antonio Light.

Sanders went on to say that he required medical attention and ultimately dropped out of school.

In a phone conversation on Thursday, Travis County Sheriff’s spokesperson Roger Wade confirmed that an arrest warrant for Hamm was issued on Aug. 24, 1993. Hamm agreed to a plea deal in 1995, according to Radar Online.

The university’s Sigma Nu chapter was dissolved after four additional fraternity members were charged with hazing. A request for response from Hamm’s representatives, who were unknown at the time, was not immediately returned.

According to university records, Hamm came on college in the fall of 1989 and departed after the same semester as the hazing. In a 2008 interview with W Magazine, Hamm said that when his father died, he dropped out of school in his second year and returned to Missouri.