On November 30, 2010, during the season finale of season three of NXT, it was announced that Conor O'Brian would be appearing on season four, with Alberto Del Rio as his mentor. He made his in-ring debut on NXT the following week, teaming with Del Rio to defeat rookie Derrick Bateman and Bateman's mentor Daniel Bryan. O'Brian won his first challenge on the January 4, 2011 episode of NXT, when he won the 'Battle of the Mic Challenge' to earn four immunity points. Two weeks later, on January 18, O'Brian was the second contestant eliminated from NXT. Earlier that night, O'Brian competed in a match against Ricardo Rodriguez in a losing effort.
In March 2011, O'Brian was selected as one of the six former NXT contestants to return to the show in its fifth season, NXT Redemption. During this season, O'Brian was mentored by Vladimir Kozlov. He was later eliminated from competition on the June 28, 2011 edition of NXT, and would later be joined, and eventually replaced, by a returning Derrick Bateman and Daniel Bryan.
In June 2012, Kenneth Cameron and O'Brian (wrestling as the Ascension) debuted on the first episode of the sixth season of NXT taped at Full Sail University, where they defeated Mike Dalton and CJ Parker. The Ascension then started a feud with the Usos on the August 15 episode of NXT, with a match between the two tag teams ending in the Ascension being disqualified; the Ascension then conducted a post-match attack on the Usos. On the August 29 episode of NXT, the Usos called out the Ascension, but the Ascension ambushed the Usos and again delivered a beatdown. On the September 5 episode of NXT, the Ascension defeated the Usos. The Ascension would then team up with Kassius Ohno to defeat the team of the Usos and Richie Steamboat on the October 17 episode of NXT. The Ascension disbanded on November 30, 2012 when Cameron was released from WWE. However, O'Brian began to wrestle with the nickname "The Ascension" and started to feud with Big E Langston for the NXT Championship. In January and February of 2013, he would compete at house shows, losing to Zack Ryder. On May 29, edition of NXT, O'Brian competed in 18 Man Battle Royal to determine #1 Contender for NXT Championship, which he could make it into final 6 men, but got eliminated by Corey Graves and Kassius Ohno. On the June 5 edition of NXT, O'Brian defeated Alex Riley. Following the match, a returning Rick Victor appeared to O'Brian on the stage during his celebration. O'Brian would be accompanied by Victor on the July 3 edition of NXT as he defeated Andy Baker, with Victor being officially recognized as his new partner in the Ascension. Then, they started a feud against the champions Adrian Neville and Corey Graves, stealing Grave's belt. On September 12, 2013, the Ascension won the Tag team Championship in a title match. O'Brian was later given the name Konnor.
On February 27, 2014 at NXT Arrival, he and Viktor successfully defended the NXT Tag Team Championships against Too Cool, repeating the feat on May 29, 2014 at NXT Takeover against the team of El Local and Kalisto.
Konnor, alongside Viktor, made his main roster debut on the September 9, 2014 edition of WWE Main Event, with the duo defeating Los Matadores in a tag-team match to promote their title defense against the team of Kalisto and Sin Cara at the NXT Takeover: Fatal Four-Way event, which they lost, ending their title reign at 364 days. On the December 12th episode of Smackdown, a vignette aired showing The Ascension with face paint, hyping there debut. The Ascension made their debut on the December 29th episode of Raw, quickly defeating The Miz and Damien Mizdow. Both he and Viktor, as part of the Ascension, would continue to squash local athletes three weeks in a row on WWE Main Event while indirectly criticizing of The Road Warriors. Their first major victory as part of the main roster was a win over The New Age Outlaws at the 2015 Royal Rumble pay-per-view. The Ascension would lose their first match as a part of the main roster on February 23 edition of Raw, losing to The Prime Time Players. At WrestleMania 31, The Ascension made their Wrestlemania debut in the André the Giant Memorial Battle Royal where both failed to win the match. On the March 30 edition of Raw, The Ascension teamed with Cesaro and Tyson Kidd to face The Lucha Dragons and The New Day in an 8 man tag but lost the match. On the May 4 episode of Raw, Ascension faced Cesaro and Tyson Kidd in a losing effort, On the May 11 episode of Raw, during a match between Curtis Axel and Damien Sandow, in the guise of Macho Mandow, The Ascension attacked Axel and Mandow. It was then announced that The Ascension would face Axel and Sandow on the Payback pre-show where they won the match. On the May 21 episode of SmackDown, the Ascension competed in a fatal four way tag match against the teams of Cesaro & Kidd, Los Mataodores and Lucha Dragons where the match was won by Lucha Dragons. At Elimination Chamber (2015), the Ascension were able to eliminate Los Matadores and The Lucha Dragons, but were eventually eliminated by The Prime Time Players inside the Elimination Chamber. On an August 27th edition of SmackDown, The Ascension faced The Dudley Boyz, but would go on to lose the match. Afterwards, The Dudleys would put Viktor through a table. On the September 3 Smackdown, The Ascension aligned themselves with Stardust by attacking Neville before their match. At Night of Champions, Stardust and The Ascension defeated Neville and The Lucha Dragons in a Six-Man Tag Team Match in the pre-show. On the Survivor Series Kickoff show, The Cosmic Wasteland (Stardust, Konnor, and Viktor), The Miz, and Bo Dallas were defeated by The Dudley Boyz (Bubba Ray Dudley and D-Von Dudley), Neville, Titus O'Neil and the returning Goldust in a five-on-five traditional Survivor Series elimination tag team match. At WrestleMania 32, Konnor competed in the Andre the Giant Memorial Battle Royale but failed to win the match.
On April 16, 2016, Konnor was suspended for 60 days for his second violation of the Wellness Program. On the June 24, 2016 episode of Superstars, Konnor made his return from suspension, where he and Viktor faced the Golden Truth (Goldust and R-Truth) in a losing effort.
On July 19, at the 2016 WWE Draft, The Ascension were drafted to SmackDown. They made their SmackDown Live! debut on the July 26 episode, where The Ascension competed in a WWE World Title No. 1 Contender's Six-Pack Qualifying Battle Royal which was won by Apollo Crews. At SummerSlam (2016), The Ascension competed in a 12-man tag team match where their team lost. They then entered the SmackDown Tag Team Championship tournament where they were eliminated in the first round by the The Usos. On the September 27 episode of SmackDown, The Ascension picked up their first win on the SmackDown brand when The Ascension and The Usos defeated Heath Slater & Rhyno and American Alpha in an 8-Man Tag Team Match. On the October 7 No Mercy pre-show, The Ascension and The Vaudevillains lost an 8-man tag team match to The Hype Bros and American Alpha. On the October 25 episode of SmackDown Live, The Ascension competed in a Survivor Series Qualifying Match but lost to The Hype Bros.