Crawford was born as her stage name Kellie Lynn Hoggart in 1974. She began her career as a teenager appearing in Pizza Hut commercials. In 1991, at age 17, Crawford along with Liza Witt and Roxanne Clark, would form an idea to bring back music from the past and recreate it as a pop music act. Initially, they tried to launch the project as a television idea set in the themed time of the 1960s. As the group experienced difficulties getting the television show off the ground, they diverted their attentions towards simply creating music. They decided to name the group the Teen Queens and from 1991 to 1993 the group released three top ten ARIA singles.
After the group split in 1993, Crawford continued to act in television and movies, and appear in commercials for companies such as Pizza Hut.
Crawford was originally cast as Tracy Russell in Australia's long running sitcom Hey Dad..! but was replaced by Belinda Emmett.
Crawford's next breakthrough would come in 1998 when she was enlisted to join the new children's band and television show Hi-5 as the group's oldest and most commercially experienced member. She features with a puppet named Chatterbox, better known as "Chats", voiced originally by co-cast member Charli Robinson, now performed by current Hi-5 House member Mary Lascaris. Kellie and Chats' segment of the show promotes and educates children on language skills and recognition of sounds and noises. Her American counterpart is Jenn Korbee.
Born in Sydney, Kellie was educated at the Meriden School in Strathfield, a suburb of Sydney. Kellie is the younger of two girls. Her older sister's name is Kylle.
Through the show, she became good friends and eventually began dating fellow Hi-5 cast member Nathan Foley. The couple became engaged in 2005 to be married in March 2007. On 7 December 2006, it was reported that Kellie and Nathan had decided to end their engagement. Apparently, their breakup had occurred some time prior to the report. It is unknown whether the breakup was on amicable terms or otherwise.
In 2007, Kellie became engaged to Addam Crawford. They married in May 2008.
In 2012, Kellie now works for a Sydney Catholic School performing arts group called CaSPA (Catholic Schools Performing Arts Sydney). Throughout this career she acts as a mentor for other young performers and takes part in stage/logistics work.