After several weeks of vignettes showcasing Matrix-like effects aired on Raw, Kim debuted on June 30, 2003 as a fan favorite, with a Matrix-inspired outfit.
Her first televised WWE match was a seven-woman battle royal on the June 30, 2003 episode of Raw with the WWE Women's Championship, then held by an injured Jazz, on the line. Kim won the match by lastly eliminating Victoria. Kim held the title for four weeks, successfully defending it once against Molly Holly, before losing it to Holly on the July 28 episode of Raw. The following week, Kim turned heel on Trish Stratus, which stemmed from a previous Raw episode where Stratus cost Kim and herself a tag match against Victoria and Holly; Kim subsequently formed an alliance with Holly to take on Stratus, defeating her and various partners on several occasions, until Stratus was later assisted by Lita. At the Unforgiven pay-per-view event on September 21, Stratus and Lita defeated Kim and Holly in a tag team match. The four women continued to feud until November, when Kim was sidelined with a broken right collarbone.
Kim returned to Raw in April 2004 and immediately reforged her alliance with Holly. In May 2004, Kim submitted then-Women's Champion Victoria twice, in singles match and a six-woman tag match, earning herself a title shot at Bad Blood. However, Lita pinned Kim on the June 7 episode of Raw, and Lita and Trish Stratus were added to the championship match. At Bad Blood on June 13, she faced Lita, Stratus, and Victoria in a fatal four-way match for the WWE Women's Championship, which was won by Stratus.
Kim participated in a battle royal on October 19 at Taboo Tuesday, which was won by Stratus. Kim, however, was released by WWE on November 3, 2004.
Kim re-signed with WWE in late 2008. She made her return as a fan favorite on the March 27, 2009 episode of SmackDown, interrupting a WWE Divas Championship match between the villainous Divas Champion Maryse and Michelle McCool by attacking both competitors. Kim made her in-ring return on the March 30 episode of Raw in an 18-Diva tag team match. She made her first WrestleMania appearance in the 25-Diva Miss WrestleMania battle royal on April 5, 2009 at WrestleMania XXV. On the April 17 episode of SmackDown, Kim defeated then-Divas Champion Maryse. This earned her a championship match the following week, which she failed to win.
On the June 29 episode of Raw, Kim was traded to the Raw brand as part of a 15 wrestler tri-branded trade between Raw, SmackDown, and ECW. A few weeks later on the August 10 episode of Raw, she became number one contender for the Divas Title by winning a fatal four-way match against Beth Phoenix, Kelly Kelly, and Alicia Fox. She, however, was unsuccessful in winning the championship on the August 17 episode of Raw, when she faced then-champion Mickie James. At Bragging Rights on October 25, Kim, with Melina and Kelly Kelly, represented Raw in a losing effort to Michelle McCool, Beth Phoenix, and Natalya, representing SmackDown.
In early 2010, a tournament was held for the newly vacated Divas Championship, and Kim defeated Jillian Hall and Alicia Fox en route to the finals. The finals were held on the February 22 episode of Raw, which Maryse won to become the new champion. The finals were originally to be held on February 21 at Elimination Chamber, but the match was changed to the team of Maryse and Kim versus Team LayCool (Michelle McCool and Layla), which was won by LayCool as a result of Maryse abandoning Kim during the match. Kim was a part of the losing side of a 10-Diva tag team match, against Team LayCool, Alicia Fox, Vickie Guerrero, and Maryse, at WrestleMania XXVI on March 28. At Fatal 4-Way on June 20, Kim challenged for the Divas Championship in a fatal four-way match that also involved then-champion Eve, Maryse, and Alicia Fox, which Fox would win to become the champion.
In early 2011, Kim participated in fewer matches on television, as she became the on-screen girlfriend of Daniel Bryan. She also began accompanying him to the ring during his matches. At that time, Bryan was managed by The Bella Twins (Nikki and Brie), and after they discovered Bryan kissing Kim backstage, they started a feud with her. The night after the Royal Rumble, Kim accompanied Bryan to ringside for his match against Tyson Kidd. After the match, the Bellas ended their association with Bryan.
For the first half of 2011, Kim feuded with Melina, due to Melina's claims that Kim was a "horrible friend". The matches between the two mainly took place on Superstars, and saw Kim emerging victorious in two singles matches on May 30 and June 23. On the August 1 episode of Raw, Kim participated in a battle royal to determine the number one contender for the Divas Championship, however, shortly after the match began, she eliminated herself. Kim left the WWE soon after.