Kendrick made his WWE debut on the January 11, 2003 edition of Velocity under the gimmick of a mascot representing the local sports team of the town in which he was competing. He continued wearing masks for several weeks, each time competing under a different identity. After acting as a telegram deliverer for Big Show to Undertaker, and getting a Last Ride for his troubles, he showed up the following week and began a series of events trying to impress the then General Manager of SmackDown! Stephanie McMahon in order to earn a contract for the WWE, including trying to last five minutes in a match with Kurt Angle. He eventually earned himself a contract on the March 20, 2003 episode of SmackDown! by defeating Shannon Moore. His first major storyline within WWE came on the May 1, 2003 episode of SmackDown!. He went under the name Spanky after he interrupted a promo by John Cena. The two feuded over their similar hip hop gimmicks, until May 22. On October 30, Spanky began teaming with Paul London until January 13, 2004 when Kendrick left WWE.
Kendrick made his return during a WWE live event on August 22, 2005, losing in a Fatal Four-Way match for the WWE Cruiserweight Championship. He then reformed a tag team with his former partner Paul London on the edition of September 30 of Velocity. On December 16, the pair remade their image, wearing theatrical masks to the ring with matching vests and shorts. They were quickly elevated into the WWE Tag Team Championship picture, receiving a non-title match against WWE Tag Team Champions MNM on the edition of February 10, 2006 of SmackDown!, which London and Kendrick lost. On April 7, they faced MNM again, picking up a win in a non-title match. Their storyline feud continued, as London and Kendrick continued their winning streak over the champions, including singles victories for both Kendrick and London on MNM members Johnny Nitro and Joey Mercury, respectively. London and Kendrick won the WWE Tag Team Title at Judgment Day, thus defeating MNM six times in a row in singles and tag team matches altogether.
Their first main competition for the titles came when K.C. James and Idol Stevens defeated the champions in a non-title match, in early August, igniting a storyline feud between the two teams. During the rivalry, WWE Diva Ashley Massaro began accompanying London and Kendrick to the ring, acting as a valet to the team while combating the actions of James and Stevens' manager Michelle McCool.
On October 14, London and Kendrick became the longest reigning WWE Tag Team Champions until 2016, surpassing MNM's previous record of 145 days. Despite this, they were still booked as the underdogs in their feuds, and this was shown when they began a losing streak to the team of William Regal and Dave Taylor. Regal defeated both in singles matches and on the December 8 episode of SmackDown!, Kendrick and London lost a non-title tag team match to the duo, although Kendrick beat Taylor on the December 9 episode of Velocity. London and Kendrick had a scheduled title defense at Armageddon, against Regal and Taylor. Before the pay-per-view, the match changed into a Fatal Four Way tag team ladder match with London and Kendrick defending their titles against Regal and Taylor, MNM, and The Hardys. London and Kendrick won the match and retained the titles.
On February 2, 2007, London and Kendrick suffered a non-title loss to the rookie team Deuce 'n Domino. In a title match at No Way Out, London and Kendrick retained the championship. London and Kendrick, however, dropped the championship to them on the edition of April 20 of SmackDown!, ending their reign at 331 days (SmackDown! was recorded on April 17). In the storyline, London missed a moonsault from the ring apron to the floor during the title match, injuring his ribs, leaving Kendrick to battle Deuce 'n Domino alone. London and Kendrick unsuccessfully competed for the title on June 1 in a triple threat tag team match, which also involved Regal and Taylor, and lost a rematch on June 15 in a standard tag team match.
Kendrick, along with London, was drafted to the Raw brand on June 17, 2007 during the Supplemental Draft. They won their debut match on Raw against The World's Greatest Tag Team on June 18. They were soon established as a threat to the tag titles, and on the edition of September 3 of Raw, they won a number one contender's match for Lance Cade and Trevor Murdoch's World Tag Team Championship. Kendrick and London then worked a feud with Cade and Murdoch, and at a house show on September 5, they defeated Cade and Murdoch to win the titles, only to lose it back to Cade and Murdoch three days later. London and Kendrick continued to feud with Cade and Murdoch and lost to the Tag Team champions at Unforgiven. For the rest of 2007, London and Kendrick mainly competed on Heat or in tag title bouts, until London got injured in late 2007. As a result, Kendrick was mainly used as a jobber on Raw, until London returned at the start of February 2008, although Kendrick still won sometimes on Heat.
In his next storyline, Kendrick abandoned London during a handicap match with Umaga. This abandonment resulted in Umaga performing the Samoan Spike on London, allowing Umaga to pick up the win over the duo. London and Kendrick still teamed together with no apparent dissension rising between the former tag team champions. After defeating Charlie Haas and Robbie McAllister on Heat, London and Kendrick said they were ready to win the World Tag Team Championship. London and Kendrick beat the champions Hardcore Holly and Cody Rhodes next week on Heat in a non-title match. However, they failed to win the World Tag Team Titles on Raw after Holly pinned London.
As part of the 2008 WWE Supplemental Draft, Kendrick was drafted back to the SmackDown brand while London stayed on Raw, thus ending the team. He made his return to the brand on the July 18, 2008 airing of SmackDown! as a major antagonist, with new ring attire defeating Jimmy Wang Yang with the help of his bodyguard, Ezekiel, who was later given a surname and became Ezekiel Jackson. Kendrick was later given the name "The Brian Kendrick". On the edition of August 22 of SmackDown, Kendrick won a 10-man battle royal to qualify for the WWE Championship Scramble match at Unforgiven. Kendrick won the interim WWE Championship title at the event, though he did lose minutes after having the longest reign as "interim" champion. As Kendrick was not the final interim champion, he never officially held the title. He later teamed with Jackson on many occasions, becoming number one contenders to the WWE Tag Team Championship held by Carlito and Primo, but they never managed to win the championship.
On April 15, 2009, Kendrick was separated from Jackson as he was drafted back to the Raw brand as part of the 2009 Supplemental Draft while Jackson was drafted to the ECW brand. He wrestled his return match on Raw on the April 27 episode, against Kofi Kingston. He won a match on Raw after defeating Carlito on the May 11 episode before declaring his intention to win the Unified WWE Tag Team Championship; in the following weeks, Kendrick tried several unsuccessful pairings. In his final match, he was defeated by Kofi Kingston while cutting a promo on Jerry Lawler. The match ended with Kendrick turning around into Trouble In Paradise. On July 30, 2009, WWE announced that Kendrick was released from his WWE contract.
On December 11, 2014, Kendrick was backstage at NXT TakeOver: R Evolution as he was reportedly trying out for a trainer role at the WWE Performance Center. Kendrick returned to WWE at the NXT television tapings on December 12, 2014, losing a dark match to Solomon Crowe. Kendrick made a televised return on the February 25, 2015 episode of NXT, losing to Finn Bálor in the main event.
On June 13, 2016, Kendrick was announced as a participant in WWE's upcoming Cruiserweight Classic tournament. The tournament began on June 23, with Kendrick defeating Raul Mendoza in his first round match. On July 14, Kendrick defeated Tony Nese in his second round match. On August 26, Kendrick was eliminated from the tournament in the quarterfinals by Kota Ibushi, with his performance moving color commentator Daniel Bryan to tears and drawing an ovation from the live crowd.
On the August 22 episode of Raw, Kendrick was announced as part of the upcoming cruiserweight division. On the September 19 episode of Raw, Kendrick made his official main roster return, winning a number one contender's fatal four-way match against Cedric Alexander, Gran Metalik and Rich Swann for the WWE Cruiserweight Championship. At Clash of Champions, he faced defending champion T.J. Perkins, but lost via submission. After the match, Kendrick embraced Perkins, but attacked him with a headbutt afterwards, establishing himself as a heel in the process. The next night on Raw, Perkins offered Kendrick a chance to redeem himself, but Kendrick attempted another attack, which Perkins was able to counter. At Hell in a Cell, Kendrick won the title from Perkins after faking an injury.
At Survivor Series in an interpromotional match, Kendrick retained the title against SmackDown's Kalisto, winning by disqualification after Baron Corbin attacked both of them. On the debut edition of 205 Live, Kendrick lost the title to Rich Swann, ending his reign at 30 days. On the December 6, 2016 episode of 205 Live, Kendrick lost to Swann in a rematch for the title. At Roadblock: End of the Line, Kendrick again failed to regain the title in a triple threat match also involving Perkins. In 2017, he developed a gimmick by offering to teaching lessons to the new Akira Tozawa, who declined. This eventually led to a street fight on the May 23, 2017 episode of 205 Live, in which Tozawa defeated Kendrick. Kendrick the began a feud with Jack Gallagher, with Kendrick impersonating and mocking Gallagher after the latter's matches. The feud ended on the edition August 29 edition of 205 Live, when Kendrick defeated Gallagher by referee stoppage in a no disqualification match, which led to Gallagher turning heel and the two regularly competing as a tag team on 205 Live, having notable matches against Kalisto and Gran Metalik.
On the December 25, 2017 episode of Raw, Kendrick suffered an injury during a match against Hideo Itami, after Itami performed a GTS on Kendrick. After going to a local medical facility, it was revealed that Kendrick suffered a fracture to his orbital bone and nasal bridge and would be out of action for two months. Kendrick returned on the April 17, 2018 edition of 205 Live, teaming with Gallagher to defeat two local competitors. On the October 3 episode of 205 Live, Kendrick was attacked by his allies Gallagher and Drew Gulak during one of Gulak's PowerPoint presentations, with Gulak calling Kendrick the "weakest link" in the group, turning Kendrick face again. On October 17 episode of 205 Live, Kendrick saved his former rival Akira Tozawa from a post-match attack by Gulak and Gallagher. On the October 30 episode of 205 Live, Kendrick defeated Gallagher after Tozawa prevented the interference of Gulak. They two sides went on to trade victories over the next few weeks. On the December 19, 2018 episode of 205 Live, Kendrick returned to his old clean shaven look and blonde hair as he and Tozawa defeated Gulak and Gallagher in a Street Fight match to end the feud. On the February 26 episode of 205 Live, Kendrick was defeated by Drew Gulak in the first round of the tournament to decide the number one contender for the Cruiserweight Championship at WrestleMania 35.
At Super Showdown, Kendrick competed in the 51-man battle royal, but was unsuccessful as the match was won by Mansoor. Following this, Kendrick would team with Akira Tozawa regularly while also managing him during his chase for the Cruiserweight Championship. In August, Kendrick and Tozawa began a feud with Jack Gallagher after Kendrick accidentally knocked Gallagher's foot off the rope during a match with Tozawa, costing him the match. On the September 10th episode of 205 Live, Kendrick and Tozawa would face Jack Gallagher and his mystery partner Kushida in a losing effort. The following week, Kendrick would face Gallagher where he lost by disqualification after assaulting Gallagher with a kendo stick. After Tozawa confronted him, Kendrick would proceed to assault him with a kendo stick, thus turning heel again. On November 15, Kendrick announced on Twitter that he would be taking an indefinite leave of hiatus from 205 Live.
He returned on the January 3, 2020 episode of 205 Live, where he cost Danny Burch his match against Ariya Daivari, and proceeded to attack him afterwards. On the January 21 episode of 205 Live, Kendrick defeated Danny Burch with the help of Daivari. During January and February 2020, Kendrick wrestled two televised matches for NXT UK, losing to Travis Banks in his first and then losing to A-Kid in his second. After a brief hiatus, Kendrick made his return on the August 28 episode of 205 Live, where he defeated Tehuti Miles. After the match, he shook hands with Miles, thus turning face in the process. Kendrick would continue wrestling on 205 Live in the coming months, losing to the likes of Ashante "Thee" Adonis (Tahuti Miles), Isaiah "Swerve" Scott and Mansoor. On the October 30 episode of 205 Live, Kendrick would team with Mansoor to defeat Ever-Rise. Following this match, Kendrick moved into a producer position, announcing his semi-retirement.
On the December 14, 2021 episode of NXT 2.0, Kendrick was involved in an angle where he was thrown down a flight of stairs by Harland after trying to escort him out of the arena. On the December 21 episode of NXT 2.0, Kendrick announced that he would make his in-ring return against Harland. However, the match never took place as scheduled and on February 1, 2022, Kendrick was released from WWE.