Lohmann discovered early on that she loved performing on stage. Her first performance was singing a song from the Walt Disney classic The Little Mermaid, at the age of eight, and she received a standing ovation. In 1989 a casting call took place for the new Disney Mickey Mouse show MMC. Although she had never worked on a TV show, Katie felt that this would be the perfect opportunity and was told she was exactly what they were looking for. However, her mother felt she was too young and the show would interfere with her education. Katie decided to take her mother's advice and wait until she was finished with school before pursuing her career.

Ten years later in 2000, she graduated from high school and relocated to Los Angeles. She had already been modeling prior to moving to Los Angeles so within a short time had been on the cover of numerous magazines all over the world.

She also appeared in a topless photo (wearing a red bikini bottom) in the Spring Break pictorial in the same issue as her Playmate pictorial.

In an interview with Howard Stern she admitted to having breast implants. She said she was always unhappy with her appearance so her mother paid for them as a present after high school graduation.

In November 2006, Lohmann was part of a trio of Playmates (along with Tina Marie Jordan and Karen McDougal) that appeared in the "Celebrity Playmate Gift Guide" pictorial of Splat magazine, a paintball enthusiasts magazine. The pictorial showcased new paintball products for the 2006 holiday season.

She currently resides in Woodland Hills, California and hopes to do more comedy work in the future, utilizing her talents to become successful and respected.