Michelle McCool competed in the 2004 RAW diva contest but didn't last too long, she was the 4th one eliminated. Even though that didn't go the way she planned WWE still saw something in her and in November of 2004 she was signed to a three year contract. She came to SMACKDOWN as a face and a personal trainer and unlike many WWE divas she was really inspired to the wrestling part of the business. She wrestled in a couple matches and feuded with Dawn Marie and Melina. She actually fought Melina in Melina's first ever match, after that match we didn't see McCool again in the WWE for almost a year. She was then sent to DSW, a developmental facility and then was sent to OVW. In June of 2006 she came back to the WWE this time as a heel and her gimmick was that of a teacher (her real life profession before wrestling). In April of 2007 she became face again when she aided Ashley who was being attacked by Jillian Hall. She was then in a feud with Victoria after insulting Victoria's boyfriend Kenny Dykstra. She has been a good friend to Chuck Palumbo and escorts him to his matches but lately their relationship has been on the rocks thanks to Jamie Noble who is infatuated with Michelle. MIchelle ended up going on a date with Noble after Noble won the date by beating Chuck Palumbo in a match. Michelle started to feel a soft spot for Jamie and later tried to make a triple team of herself, Jamie Noble and Chuck Palumbo. Noble and Palumbo hated each other but would try to get along in front of Michelle. On the 01-25-08 Smackdown the triple team had a match in which Noble and Palumbo would get into an argument. Michelle tried to stop the nonsense but was betrayed by Chuck Palumbo who threw her to the ground. Michelle McCool then started appearing on Jamie Noble's side of the ring as Palumbo became a heel and Noble a face. On the April 4, 2007 edition of Smackdown Michelle was announced as the winner of the Smackdown diva contest, a competition that had been going on for weeks. She began feuding with Victoria (one of the diva competitors who got eliminated) who is really angry that Michelle won the contest. Then Victoria had a new friend and partner who came to Smackdown named Natalya. Natalya quickly began a vital enemy of Michelle.On the July 4th edition of Smackdown McCool won the Golden Dreams Diva match which earned her the right to take part in the first match for the newly created divas championship belt. The title was created by Smackdown GM Vickie Guerrero. The other diva who was to compete to become the first to wear the new belt was Natalya. They met up July 20, 2008 at the Great American Bash with Michelle McCool winning and becoming the first to wear the Divas championship belt.
On September 7, 2008 at Unforgiven McCool would successfully defend her WWE Divas title by defeating Maryse.
On the November 14, 2008 edition of Smackdown Michelle McCool would have to defend her title against her friend Maria, who had won the honor of becoming the number one contender for the Divas championship after beating other Divas at the Las Vegas poll match on the October 17, 2008 edition of Smackdown. Weeks leading into the match the two friends had not been too pleased with each other but still had a handshake before their match. McCool was able to defend her title once again by beating Maria.
McCool would team up Maria at Survivor Series as well as the other Smackdown Divas as they would battle the Raw Divas. It was McCool, Maria, Victoria, Natalya and Maryse against Beth Phoenix, Candice Michelle, Kelly Kelly, Jillian and Mickie James. Victoria and the Smackdown Divas were defeated by the Raw Divas.
On the December 26 episode of SmackDown!, McCool lost the Divas Championship to Maryse in a match which involved Maria as the special guest referee. Following the match, Michelle officially turned heel by attacking Maria and blaming her for the loss.
In the following weeks McCool would attack Eve Torres from behind and then later attacked Victoria from behind. On the January 16, 2009 edition of Smackdown, Victoria would approach McCool and tell her that she is not like any of these little girl divas and that Michelle had messed with the wrong person. McCool and Victoria battled in a match that night and Michelle McCool would win the match in what would be Victoria's final match as she afterwards announced her retirement from the WWE.
In many consecutive weeks she also attacked Eve Torres and Victoria. On January 19 she defeated Victoria in her final WWE match. A few weeks later she defeated Eve Torres in her debut match via the heel hook but after the match Maria came to Eve's aid after Mccool refused to let go of the hold. The next week Maria defeated McCool with the help of Eve Torres.
On February 20 on SmackDown, she teamed with Maryse to defeat Maria and Eve Torres. A few weeks later on SmackDown she once again teamed with Maryse in a losing effort against Melina and Maria after Michelle refused to tag in, following the bout the two divas got into a brawl. On the March 27 episode of Smackdown she got her rematch for the Diva's Championship against Maryse. During their match, Gail Kim made her Smackdown debut by succeeding in planting a dropkick on Michelle from the top rope, causing her to lose via disqualification. Maryse still now remains Diva's Champion.