Gert Steinheimer was born in Ottenhöfen on July 7th 1944. He grew up in Mannheim, where he started out as a lighting grip at the national theatre. After gathering experience as an assistant director at the same venue, he began directing plays in the 1960s and 1970s. In the early 1980s, he switched mediums and freelanced as a writer and director for German television network ZDF. The following years, he completed numerous documentaries and shorts.

In 1986, he transferred to the SWR network in Baden-Baden, where he also directed his first made-for TV film: The comedy "Zweikampf" won a screenplay award at the Monte Carlo Television Festival. Three years later, Steinheimer was awarded a Grimme prize for the TV-miniseries "Atlantis darf nicht untergehen". Till the end of the 1990s, he completed films like, "Der Gaukler", "Liebe, Tod und Eisenbahn" (starring Heiner Lauterbach) and the noir comedy "Killer". He garnered much critical acclaim for his feature film "Bis Dann" (1996), a bittersweet comedy about a lonely retirement home resident who starts writing love letters to an 18-year-old girl and pretends to be nineteen. From 1998 on, Steinheimer mainly works as scriptwriter for crime series like "Männer vom K3" and "Großstadtrevier".

After an eight year break from directing, he presents his cinema debut in 2010: The horror film " Black Forest" tells the story of four young tourists who are haunted by a dark force during their vacation in the woods.