In 1995, he briefly appeared in the World Wrestling Federation as Xanta Klaus. At In Your House 5: Seasons Beatings in December, while Savio Vega and "Santa Claus" were at ringside handing out presents and playing to the fans, villainous manager "Million Dollar Man" Ted DiBiase appeared. DiBiase proclaimed that everyone had a price, even Santa. As Vega argued with DiBiase, "Santa" jumped him from behind and attacked him. DiBiase laughed his trademark laugh and introduced this warped Santa as Xanta Klaus, from the South Pole who steals presents. As Xanta, he made only a couple more appearances (one on the following night's Monday Night Raw), before never being mentioned again.
In 1997, he signed with Extreme Championship Wrestling (ECW) and found success as Balls Mahoney. Capitalizing on the ECW crowd's lust for violence and the hardcore attitude Mahoney was never seen without his signature steel chair, usually with some kind of writing or sign placed on it, which he would use to bash any opponent at any time. While in ECW, he teamed with Axl Rotten, a similar hardcore and violent wrestler, and the duo became informally known as "The Hardcore Chair Swingin' Freaks". They feuded with The Dudley Boyz (Buh Buh Ray and D-Von) during their tenure.
Mahoney made his pay-per-view debut at November to Remember, participating in a Four-Way Dance match for the ECW Tag Team Championship, along with his partner Rotten; The F.B.I. (Tracy Smothers and Little Guido) retained the titles. At Living Dangerously, they participated in a three-way dance, along with the Dudleyz in a losing effort to Spike Dudley and New Jack. Mahoney and Rotten got another chance at the titles at Wrestlepalooza against Chris Candido and Lance Storm, but lost.
After failing to win the titles with Rotten, Mahoney found a new partner in Masato Tanaka. At November to Remember, the two defeated the Dudley Boyz to win the World Tag Team Championship, thus beginning Mahoney's first reign as tag champion. Six days later, Mahoney and Tanaka dropped the title to the Dudleyz in a rematch. At Guilty as Charged, Mahoney and Rotten defeated the F.B.I. and Danny Doring and Roadkill in a three-way dance.
Mahoney's first singles match at a pay-per-view was a victory over Steve Corino at Living Dangerously. Shortly after, Mahoney formed a tag team with Spike Dudley. At Hardcore Heaven, the two faced the Dudleyz in a championship match but failed to win the title. The two teams faced in a rematch at Heat Wave, and this time, Mahoney and Dudley won the match and the World Tag Team Championship, marking Mahoney's second individual reign. At a show in August, the duo lost the titles to the Dudleyz.
On the edition of August 14,1999 of ECW on TNN, Mahoney and Dudley defeated the Dudleyz in another rematch to win back the World Tag Team Championship. On the edition of August 26 of ECW on TNN, they lost the titles to the Dudleyz again. At Anarchy Rulz, ECW World Television Champion Rob Van Dam was scheduled to defend his title against Johnny Smith but before the match, Mahoney, Rotten, and Dudley attacked Smith and took him out of the match. Mahoney then challenged RVD for the title but lost the match.
At November to Remember, Mahoney and Rotten lost to Da Baldies (Angel, Tony DeVito, Vito LoGrasso, and P.N. News) in a 4-on-2 handicap match. At Living Dangerously, he defeated Kintaro Kanemura. He met his former tag team partner, Masato Tanaka in the first match at Hardcore Heaven, which Tanaka won.
At Heat Wave, he lost a match to F.B.I. member Sal E. Graziano. He formed a tag team with Chilly Willy and the duo feuded with Da Baldies. After losing a match to Da Baldies at Anarchy Rulz, Mahoney and Willy defeated them in a flaming tables match at November to Remember. At Massacre on 34th Street, Mahoney lost to EZ Money.
Mahoney's final ECW appearance was at ECW's final pay-per-view Guilty as Charged where Mahoney and Chilly Willy's match with Simon Diamond and Johnny Swinger ended in a no contest.
In 2005, Mahoney made a non-wrestling appearance at the World Wrestling Entertainment-promoted ECW One Night Stand reunion show, taking part—alongside Axl Rotten—in a brawl with Kid Kash, Tommy Dreamer, The Sandman, the Dudley Boyz, and The Blue World Order (bWo) before the main event. After the main event, Mahoney and Rotten returned to the ring to brawl with the "invading" Raw and SmackDown! wrestlers.
In 2006, when WWE relaunched ECW as their own brand, one of the first announcements was the signing of Balls Mahoney. His signing was announced with that of Axl Rotten, but when Rotten missed some WWE dates and was released, Balls was left to start a singles career. During the "cross promotion" hype, Balls appeared on the June 5 edition of Raw with other ECW wrestlers who proceeded to attack WWE Champion John Cena. He appeared again as a part of the ECW team in the "WWE vs. ECW team battle royal" at the WWE vs. ECW Head to Head event on June 7. At One Night Stand, Balls defeated Masato Tanaka in a match following a chair shot to Tanaka's head.
When ECW on Sci Fi debuted, Balls started off with a small role in the company, having sporadic matches and little else. Once the show got going he started to appear in vignettes talking about how tough he was, elevating his role on the show. On the edition of September 5 of ECW on Sci Fi, Mahoney entered a feud with Kevin Thorn after Thorn and his valet Ariel cost him a match against Stevie Richards and the next week, René Duprée.
The following week, he brought Francine to ringside with him, marking her first televised appearance at the revived ECW ring, where she proceeded to get into a catfight with Ariel. That pairing, however, was short lived as Francine was released shortly after. At December to Dismember, Mahoney defeated Matt Striker in a Striker's Rules match.
On the edition of January 2, 2007 of ECW on Sci Fi, Mahoney had one of his front teeth legitimately knocked out during a match with Kevin Thorn. Shortly after, Balls began a short feud with Snitsky. On the edition of June 5 of ECW, Balls, Tommy Dreamer, and the Sandman faced Bobby Lashley in a 3-on-1 Hardcore Handicap match for the ECW Championship, in which they were defeated.
On the August 7, 2007 episode of ECW, Balls went against The Miz in a losing effort. During and after the match, it appeared that Kelly Kelly was concerned about him. Over the weeks that followed, he attempted to ask her out and flirted with her backstage, but was interrupted by The Miz, Brooke, and Layla before Kelly could get a word in. Regardless, Kelly still showed interest in him each week, wishing him good luck before his match and cheering him on during his match. He asked if she would go out with him to which she could not respond due to The Miz taking her backstage. Weeks later, however, Kelly asked him out, starting an on-screen relationship.
On February 29, 2008, Balls made his return to television on SmackDown!, taking on Big Daddy V. The match went to a no contest after The Undertaker chokeslammed Mahoney. Mahoney was released from his WWE contract on April 28, 2008.
On April 12, 2016, Mahoney passed away.