Marshall first entered WWE as a contestant in the 2005 Raw Diva Search, in which she eventually finished fourth. Despite not winning the Diva Search contract, Marshall was signed to a deal soon after the contest finished. In December 2005, she joined the SmackDown! roster as a backstage correspondent, interviewing the brand's superstars during the shows.
Her first actual feud on the brand came against Jillian Hall. Marshall defeated Hall in her debut match—a "Divas Uncovered" match—on the March 10, 2006 SmackDown!. Kristal was defeated by Jillian Hall but was later comforted by Michelle McCool. When Diva Search winner Ashley Massaro joined the SmackDown! brand, Marshall was turned heel and put into an angle where she was jealous of Massaro's Diva Search win. She was aligned with Michelle McCool and the two feuded with Massaro and then-babyface, Jillian Hall, leading to a fatal four-way Bra and Panties match at The Great American Bash, during which Marshall was legitimately injured, though she did not miss any time. In September, the next year's Diva Search winner, then-babyface, Layla El, arrived on the brand, and Marshall was put into a feud with her. This feud had Marshall aligned with Mike "The Miz" Mizanin against Layla and the Boogeyman.
In February 2007, Marshall became a face again and began a storyline which had her as a close friend of then-babyface, Vickie Guerrero, who was mysteriously planning something, and then flirting with SmackDown General Manager Theodore Long. After Marshall confessed her love for Long, she convinced him to hire Guerrero as his assistant, leaving her in charge of the show on occasion. Eventually Long proposed marriage, only to suffer a heart attack during the in-ring wedding on September 21. She was released from her WWE contract a few weeks later.