On the August 29, 2008 episode of SmackDown, Brie debuted and defeated Victoria. She quickly began a scripted rivalry with Victoria and Victoria's accomplice, Nattie Neidhart, who was now using the ring name Natalya, and had a series of matches against them. In each match Brie would roll out of the ring and go underneath it, emerging and appearing revived, and then win the match. On the October 31 episode when Brie went under the ring Victoria grabbed her legs, but a second pair of legs kicked her off, implying that a second person was under the ring. The following week on SmackDown, Brie picked up a win against Victoria and then ran under the ring to escape Natalya and Victoria, but Victoria and Natalya both reached for Brie under the ring, resulting in both Nicole and Brie being pulled out. The twins then attacked them and celebrated afterward. Nicole was then introduced as Nikki. The twins had their first official match as a team on the November 21 episode of SmackDown, defeating Victoria and Natalya. They continued competing in tag team matches for the next few months.
Starting in November, they developed an on-screen relationship with The Colóns (Carlito and Primo), appearing in numerous backstage segments with them, and accompanying them to the ring. In February 2009, the storyline expanded to include John Morrison and The Miz, who flirted with the Bellas and took them on a date on Valentine's Day. The date provoked a rivalry between the teams of The Miz and Morrison and Primo and Carlito, with the four competing for the affection of The Bella Twins, who were seemingly unable to choose between them. On March 17, on ECW, Carlito and Primo, aiming for Morrison and The Miz, accidentally spat apples in the face of Brie. Nikki started to laugh at Brie's misfortune, and a fight broke out between the two of them, which led to Nikki leaving with The Miz and Morrison, while Brie stayed with Primo and Carlito. Brie won her first match over Nikki in a six-person intergender tag team match on SmackDown the following week. On ECW on March 31, Nikki pinned Brie in their first singles match against each other, after a distraction from Morrison and The Miz.
On April 15, 2009, The Bella Twins were both drafted to the Raw brand as part of the 2009 Supplemental Draft. On April 27, Brie made her Raw in-ring debut in an eight-Diva tag team match, which her team won. Nikki also made an appearance, reuniting with her twin, as she was under the ring to help out Brie during her match. Nikki then made her official in-ring debut for the brand the following month, in a battle royal but was eliminated by Beth Phoenix.
On June 29, 2009, they were both traded to the ECW brand. They debuted on ECW the following night on The Abraham Washington Show, as the special guests. They quickly developed a storyline feud with Katie Lea Burchill, when Nikki defeated her in a match by switching places with Brie behind the referee's back. The following week on WWE Superstars Brie defeated Burchill after a similar switch, and the feud ended in September, when Nikki defeated Burchill on Superstars.
On October 12, the Bellas were sent back to Raw as part of a tri-branded divas trade, where they predominately appeared in backstage segments with the weekly guest stars and only occasionally competed in matches. On the January 4, 2010, episode of Raw, Brie participated in a tournament for the vacant WWE Divas Championship, but lost to Maryse in the first round, when a switch resulted in Nikki being pinned. In June 2010, they developed a feud with Jillian Hall, when Brie defeated her after switching places with Nikki. The following week, Nikki defeated Hall after switching with Brie. The feud was exacerbated when the Bellas acted as the special guest referees during one of Hall's matches. During the match, Hall attacked both twins, but lost the match when Nikki made a fast count, allowing her to be pinned by Gail Kim. The next week on Superstars, the twins defeated Hall and Maryse in a tag team match to complete the storyline.
On August 31, The Bella Twins announced they would be part of season three of NXT, mentoring Jamie. Jamie was the first rookie eliminated on the October 5 episode of NXT. In November, the twins began a storyline with Daniel Bryan, when Brie accompanied him to the ring for his match. Following his win, Nikki ran out and the two fought over Bryan's affection, until Bryan broke it up and had them hug each other. They began to manage Bryan and frequently accompanied him to the ring over the next two months. In January 2011, both Bellas turned into villainous characters when they discovered Bryan kissing Gail Kim backstage and then assaulted Kim. They continued to attack Kim, both at the Royal Rumble and on Raw, and on February 7, they teamed with Melina in a losing effort to Kim, Eve Torres, and Tamina.
The Bellas began feuding with Torres after they appeared as lumberjills during a Divas Championship match between Eve and Natalya on the February 14 episode of Raw. Following the match, they attacked Torres backstage before Kim and Natalya stopped them. The next week, The Bella Twins defeated Torres and Kim in a tag team match. The following week, Nikki won a Divas battle royal to become the number one contender for the WWE Divas Championship, and faced Torres for the championship on March 7, but was unsuccessful. On April 11 Brie defeated Torres to win the WWE Divas Championship, marking the first time either twin had held a championship in WWE. Brie went on to successfully defend the championship against Kelly Kelly at Over the Limit, after switching places with Nikki. On a special "Power to the People" episode of Raw on June 20, Brie defended her WWE Divas Championship against Kelly, who was selected by voters. Kelly defeated Brie and won the Divas Championship. On July 17, Brie challenged Kelly for the WWE Divas Championship in a rematch at the Money in the Bank pay-per-view, but failed to win.
The twins spent the majority of the rest of the year in tag team matches, regularly facing Kelly and Torres. The Bellas began to show friction for the second time since joining WWE in March 2012 after both lost to AJ in singles competition. After Brie's match with AJ, Nikki revealed that Brie was rooting for Team Johnny in the 12-man tag team match at WrestleMania XXVIII, whilst Nikki was rooting for Team Teddy, thus furthering their dissension.
On the April 6 episode of SmackDown, Nikki defeated the Divas Champion Beth Phoenix in a non-title match, after Kelly distracted Phoenix. On April 23, Nikki defeated Phoenix in a lumberjill match on Raw for the WWE Divas Championship. Brie lost Nikki's championship to Layla at Extreme Rules after "Twin Magic" failed, ending her Divas Championship reign after only a week. The following night on Raw, they competed in their last match with the WWE, failing to win back the Divas Championship from Layla in a triple threat match. Later that night, WWE announced on their website that the twins had been fired by Executive Administrator Eve Torres.
The Bella Twins returned to WWE on the March 11, 2013, episode of Raw in a backstage segment with Team Rhodes Scholars (Cody Rhodes and Damien Sandow). On the March 15 episode of SmackDown, The Bella Twins attacked The Funkadactyls (Cameron and Naomi), and the following week interfered in matches between Team Rhodes Scholars and Brodus Clay and Tensai, but they were attacked by Cameron and Naomi. The Bella Twins made their in-ring return facing and defeating The Funkadactyls on the March 27 episode of WWE Main Event following interference from Rhodes, and also defeated them on Raw. The Bella Twins were scheduled to participate in an eight-person tag team match with Team Rhodes Scholars against Tons of Funk (Clay and Tensai) and The Funkadactyls at WrestleMania 29, but the match was cancelled due to time restraints. The match instead took place the following night on Raw, where Tons of Funk and The Funkadactyls emerged victorious. They continued to feud with The Funkadactyls, defeating them in standard and six-Diva tag team matches. In June 2013, Nikki suffered a fractured tibia.
Upon the debut of the Total Divas reality television program in July 2013, the Bellas began feuding with their co-star on the show, Natalya. Brie and Natalya went on to trade victories in singles competition on Raw and at SummerSlam. The cast of Total Divas then transitioned into a scripted feud with WWE Divas Champion AJ Lee, who mocked the show and cast. At Night of Champions, Brie unsuccessfully faced Lee for the Divas Championship in a four-way match also involving Natalya and Naomi. Following Brie's real-life engagement to Daniel Bryan, their relationship began to be acknowledged on WWE television. Continuing their feud into October, Brie and AJ faced off at the WWE Battleground and Hell in a Cell pay-per-views for the WWE Divas Championship, but Brie was unsuccessful. Nikki returned to in-ring action on the October 25 episode of SmackDown, losing to AJ. At Survivor Series the following month, the twins were part of the victorious Team Total Divas. The twins failed to win the Divas Championship again at WrestleMania XXX in the Divas Invitational match, which was won by AJ.
In April 2014, Brie became involved in her husband Daniel Bryan's ongoing storyline with Stephanie McMahon and Kane. As part of the storyline, McMahon threatened to fire Brie if, an injured, Bryan did not relinquish the WWE World Heavyweight Championship, which forced Brie to quit before slapping McMahon in the face. After Brie quit, McMahon put Nikki in several handicap matches as punishment. Brie returned to WWE television, appearing in the crowd on July 21; following a confrontation, McMahon slapped Brie and was subsequently arrested. In order to have Brie drop the storyline charges, Brie was rehired and received a match against McMahon at SummerSlam. At SummerSlam, Brie lost to McMahon when Nikki attacked Brie. The next several weeks saw the sisters fight in several backstage and in-ring segments, including a cameo appearance from Jerry Springer on Raw on September 8. As part of the storyline, McMahon declared Nikki the face of the Divas division and granted her a match at Night of Champions for the WWE Divas Championship, but she failed to win. Nikki then obtained permission to begin forcing Brie to compete in handicap matches, similar to her punishment at the hand of McMahon; Brie was able to defeat Eva Marie and Cameron on Raw on September 29 and the Slayers (Layla and Summer Rae) on Main Event that same week. This led to a match between the two at Hell in a Cell, which Nikki won, forcing Brie to act as her personal assistant for thirty days. The following week, Nikki won a Halloween costume battle royal to become the number one contender for the WWE Divas Championship.
Nikki received her title match against AJ at Survivor Series, which she won, with Brie's help, to become a two-time Divas Champion. Brie apparently reconciled with her sister at this point. At TLC: Tables, Ladders and Chairs on December 14, Nikki cheated to retain her title against AJ, while Brie continued to refuse to explain why she had suddenly reconciled with her sister despite Nikki's mistreatment of Brie for months. Paige and AJ formed an alliance to challenge the Bellas, and at WrestleMania 31, the pair defeated Brie and Nikki in a tag team match. At Extreme Rules in April, Nikki retained her championship against Naomi. During the feud against Naomi and her bodyguard Tamina Snuka, both Bellas turned babyface. At Elimination Chamber in May, Nikki retained her championship against Naomi and Paige in a triple threat match, with Brie banned from ringside. In June, the twins became villains again by employing Twin Magic, which helped Nikki retain the championship against Paige on the June 1 episode of Raw and at Money in the Bank. During the feud with Paige, Alicia Fox allied with the Bellas to form "Team Bella". At The Beast in the East on July 4, Nikki retained the championship against Paige and Tamina. After weeks of Team Bella outnumbering Paige, Naomi, and Tamina, Stephanie McMahon called for a "revolution" in the Divas division and introduced the debuting Charlotte and Becky Lynch as Paige's allies. NXT Women's Champion Sasha Banks would then debut and ally with Naomi and Tamina, leading to a brawl between the three teams. At Battleground, a triple-threat match took place with Brie Bella representing Team Bella, against Charlotte of Team Paige, and Sasha Banks of Team B.A.D. in a losing effort with Charlotte picking up victory. The three teams would ultimately face off at SummerSlam in a three team elimination match. Team Bella would first eliminate Team B.A.D. when Brie pinned Tamina, however PCB would win the match when Brie was pinned by Becky Lynch. Bella spent the rest of 2016 teaming with Fox in losing efforts after Nikki was away with injury.
After defeating Charlotte in a non–title match on the February 1 episode of Raw, Brie was granted a match for the WWE Divas Championship at Fastlane on February 21, where she failed to capture the title. During that time, Team Bella quietly disbanded and Brie transitioned into a fan favorite, while Fox remained villainous.
Upon March, Brie was placed in a feud with Lana, who argued that Brie's fans only supported her out of pity for having a "bad husband", and went on to distract Brie during her matches and attack her after the matches. Brie then aligned herself with fellow Total Divas Alicia Fox, Natalya, Paige and the returning Eva Marie. While, Lana aligned herself with Team B.A.D., Summer Rae and the returning Emma. The feud led to a 10-diva tag team match at WrestleMania where they won and where Nikki Bella, who was still recovering from a neck surgery made a surprise return reuniting with Brie. Three days later, on April 6, Brie confirmed that she would be taking an extended break from in–ring competition, citing family reasons, while also stating that she will continue working for WWE as an ambassador.