Gertler started out in the comics field providing the English language adaptation of Speed Racer for Now Comics in 1988/89. In the mid-1990s, he contributed to Wendy and Richard Pini's ElfQuest, as well as Caliber Comics' Negative Burn anthology. Gertler founded the About Comics publishing company, which is neither "a mainstream comics publisher, nor an alternative comics publisher". About Comics founded the 24 Hour Comics Day event, and has published works by such comics writers as Kurt Busiek and Charles M. Schulz, as well as producing books such as Panel One and Panel Two, featuring comic scripts written by a number of top comics writers.

He is also the self-published creator of the comics mini-series The Factor, about a superhero who is never actually seen in the comic. He was nominated for the 1999 Eisner Award for Talent Deserving of Wider Recognition for his work on The Factor.Kallies, Christy. " Nat Gertler: Eisner Nominee" [interview]. Sequential Tart. May 1999.