In 2005, Mahoney made a non-wrestling appearance at the World Wrestling Entertainment (WWE) 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 (denting the chair) 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 September 5 edition 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 January 2, 2007 edition of ECW on Sci Fi, Mahoney had one of his front teeth legitamately knocked out during a match with Kevin Thorn. Shortly after, Balls began a short feud with Snitsky. On the June 5 edition 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. Without appearing on television for several months, Mahoney was released from his WWE contract on April 28, 2008.
On April 12, 2016, Mahoney passed away.