In late December 2011, Rose, as Leo Kruger, appeared at several WWE house shows, losing to Alex Riley on December 27 and 28. On December 30, he teamed with Riley and Mason Ryan to defeat Tyler Reks, Curt Hawkins, and JTG in a six-man tag team match at a Raw brand house show.
When WWE made NXT its developmental program in 2012, Kruger's NXT television debut took place on June 27 episode of the rebooted WWE NXT taped at Full Sail University, where he defeated Aiden English. On the August 1 episode of NXT, Kruger was inserted into the Gold Rush Tournament to crown the first NXT Champion, where he was defeated by Richie Steamboat in the quarter-finals. In September, Kruger's character was altered into that of a deranged hunter and mercenary. In December, Kruger formed an alliance with Kassius Ohno; Kruger and Ohno defeated Tyson Kidd and Justin Gabriel on January 2, 2013 episode of NXT. On the January 16 episode of NXT, Kruger defeated Trent Baretta. On the January 30 episode of NXT, Ohno and Kruger entered the NXT Tag Team Championship Tournament to crown the inaugural champions and defeated Alex Riley and Derrick Bateman in the first round. On the February 6 episode of NXT, Kruger and Ohno were defeated by Adrian Neville and Oliver Grey in the semi-finals. Kruger then moved on to feud with Justin Gabriel when he attempted to attack Gabriel's injured partner, Tyson Kidd; Kruger won the series of matches 2–1. Kruger next set his sights on Bo Dallas' NXT Championship. On July 18 NXT, Kruger won a triple threat match against Sami Zayn and Antonio Cesaro to become number one contender. On August 7, Kruger fought Dallas for the NXT Championship, but lost. Kruger eventually feuded with Zayn with the feud culminated in Zayn winning a two-out-of-three falls match on the January 1, 2014 NXT.
Kruger was then removed from television, and began wrestling at house shows as a new character called Adam Rose. As Rose, he returned to television on the 6 March 2014 episode of NXT, with his new character being an organizer of parties with various colorful costumed party-goers, who accompany him during his ring entrance. Rose's supporters were called Rosebuds.
In August 2014, within NXT, Rose and Sami Zayn participated in a tournament for an opportunity at the NXT Tag Team Championship, defeating Justin Gabriel and Tyson Kidd in the first round, but they lost in the second round to The Lucha Dragons (Kalisto and Sin Cara), with the Adam Rose character being pinned for the first time. On the 4 September episode of NXT, Rose suffered his first singles loss at the hands of Tyson Kidd.
After WrestleMania XXX, on the April 7 Raw, WWE aired introductory vignettes for Rose. Rose made his main roster debut on the 5 May episode of Raw, by interrupting Zeb Colter and Jack Swagger. Rose continued to distract Swagger during his matches, leading to Swagger losing. Rose wrestled his first Raw match on the 26 May episode of Raw in a winning effort against Damien Sandow. During the match Swagger and Colter interfered, holding one of Rose's party members hostage. Rose saved his friend after winning the match despite the distraction. Rose defeated Swagger on the 30 May episode of SmackDown and the 2 June episode of Raw. Rose made his first pay-per-view appearance at Money in the Bank, where he defeated Damien Sandow. On the Battleground pre-show, Rose defeated Fandango. After over a month of inactivity, Rose returned on 1 September episode of Raw, where he defeated Titus O'Neil.
On 22 September episode of Raw, Rose teamed with his popular Rosebud, The Bunny (a 'highly athletic individual' in a rabbit suit) for the first time, as they defeated Heath Slater and Titus O'Neil. On the 15th Anniversary episode of SmackDown for 10 October, Rose suffered his first main roster loss at the hands of Kane.
On the 31 October episode of SmackDown, WWE teased dissension between Rose and The Bunny when R-Truth hinted that The Bunny was upstaging Rose. After The Bunny cost Rose a match, The Bunny was assaulted and abandoned by Rose, but continued supporting Rose for his next match and often started causing Rose to lose some matches after the attempts to help him out backfired. In response, Rose allowed The Bunny to submit to Tyson Kidd during an "inter-species" match, rather than saving him when Kidd placed him in the sharpshooter. The Bunny teamed up with Rose at Survivor Series to take on Slater Gator (Heath Slater and Titus O'Neil) in a tag team match. The Bunny won the match but Rose was clearly displeased. The Bunny and Rose then failed to win a tag team turmoil match, which granted the winners a shot at the WWE Tag Team Championship. In December 2014, the Bunny won a Slammy Award.
Rose then feuded with Kane, with Kane defeating him and The Bunny sustaining a neck injury from receiving a tombstone piledriver when he was just helping out Rose. On the 22 December episode of Raw, Rose snapped after a quick loss to R-Truth and viciously attacked The Bunny, turning heel in the process; this beat down marked The Bunny's last appearance. As part of his heel turn, Rose started to push around his Rosebuds, behaving like a bully. He next feuded with the returning Zack Ryder, with the pair exchanging victories. Rose was one of the participants in the second annual André the Giant Memorial Battle Royal at WrestleMania 31. Rose however did not win the match.
In late April, Fandango split away from Rosa Mendes and Adam Rose was seen talking to her. A week later, Rosa cost Fandango a match with Rose, and became Rose's valet instead after a kiss. On 14 May, Rose informed his Rosebuds that the party was "officially over", at this point completely ending his "Party animal" gimmick.
On the 22 June episode of Raw, Rose's gimmick was slightly altered to a pompous artiste, exclaiming that the WWE Universe had no idea of true art or passion, hyping up the reveal of his "masterpiece" in the process. The storyline was never resolved. Rose re-emerged on the 29 August episode of Main Event, sporting generic black boots and tights, a plain grey shirt, glasses, and an altered gimmick again. Though he eventually submitted to Jack Swagger, he declared in a pre-match promo his intentions to "poop on everybody's party". On the 5 October episode of Raw, Rose shared a "cryptic message", saying, "All I wanted to do was put smiles on little children's faces. Well, poop." The camera then tilted down onto what seemed to be the Bunny's mascot head. On the 3 November edition of Main Event, during and after defeating Fandango, this mystery bunny person was seen at ringside leaving Rose surprised. Rose soon formed a tag team with Brad Maddox. However, the team would be short-lived as Maddox was released from his contract on 25 November. Following Maddox being released from the company, on the 30 November 2015 edition of Raw, Rose debuted a segment entitled The Rose Bush, in which he started talking about all the "dirt" in WWE.
On the 4 January, 2016 episode of Raw, Rose, along with Heath Slater, Curtis Axel and Bo Dallas, debuted as a new stable and went on to assist Slater in defeating Dolph Ziggler. On the 11 January episode of Raw, now billed as The Social Outcasts, the group would face The Wyatt Family to a no contest when Ryback interfered. On the 24 January 2016 SmackDown, the four defeated the team of Goldust, Damien Sandow, Jack Swagger and Zack Ryder in an eight-man tag match. On the 8 February episode of Raw, Rose defeated Titus O'Neil. At WrestleMania 32, Rose competed in the Andre the Giant Memorial Battle Royal, but was eliminated by the eventual winner Baron Corbin. On the 11 April episode of Raw, Rose lost to Apollo Crews in what would be his final match in WWE.
On 16 April 2016, WWE announced that Rose was suspended for 60 days after his second violation of the company's Wellness Program. On May 23, 2016, the company released Rose.