Bert Grimm (born Edward Cecil Reardon, later known as Bertram Cecil Grimm, February 8, 1900 – June 15, 1985) was an American tattoo artist considered the "grandfather of old school". Grimm's work contributed to the development and popularity of the American Traditional tattoo style.^[1] He tattooed Bonnie and Clyde and Pretty Boy Floyd, among others.^[2][3]

Edward Cecil Reardon was born in Springfield, Missouri^[4] to John Elmer Reardon (1862–1945) and his wife Carrie Elizabeth Shull Reardon (1863–1923), one of twelve children. He grew up in Portland, Oregon.^[5] At some point he changed his name to Bertram Cecil Grimm. He married Julia Florence Lechler (1910–1984) on February 7, 1931. Grimm died 15 June 1985 in Warrenton, Oregon.

Early in his professional career, he spent a season with the Buffalo Bill Wild West Show.^[6] Grimm opened his first tattoo store in Chicago in 1916.^[7] Over the years, he operated stores in Honolulu, Salt Lake City, Las Vegas, Seattle, Los Angeles, Long Beach, St. Louis, Portland, and coastal Oregon and China.

His shop in Long Beach, at the Nu-Pike, was later owned by Bob Shaw.^[8] Proximity to the Long Beach Naval Shipyard, and its many sailors on extended leave during retrofitting, supported an ink economy because of the tradition of sailor tattoos.^[8] Kari Barba purchased Grimm's shop in 2003.^[1]

Grimm was a promoter of Ben Corday, Lyle Tuttle and Ed Hardy.