Commissioned by Plan Tzu (a.k.a. Yellow Claw) as part of a complicated plan to establish his unwitting successor, FBI agent Jimmy Woo, as a great hero, the robot M-11 was completed in 1954 by an unidentified professor. Concerned at creating a killing machine completely under the control of Plan's Atlas Foundation, and pressured to hand over M-11 before he could complete the programming modifications he wanted, the scientist took the drastic step of having the robot electrocute him, correctly reasoning that somehow part of his displaced life essence would encode itself in its neural net, giving it free will and emotions. After slaying him, M-11 left the lab and walked into the sea, where it lay inert.

Four years later, Plan Tzu kidnapped President Elsenhower, and as he intended, Woo gathered together a team of "G-Men" to rescue him. M-11 had been found by the Atlantean Namora, while she was searching for her missing cousin Namor; she informed Woo of the machine, and he retrieved it. Its teammate Marvel Boy (Robert Grayson) used Uranian know-how to restore it to working order; M-11 worked with the group out of choice and a growing loyalty to Woo, but pretended to be controlled by a voice-activated radio device Woo carried. After a successful first mission, the G-Men worked together for another six months, battling foes such as the mysterious Foundation and the cosmic-ray mutated dog Laika, before instructions came from above to disband. M-11 was covertly retrieved by Plan Tzu, and over the succeeding decades it allowed him to make numerous upgrades to its systems.

Recently Plan Tzu moved to pass on his mantle to Woo. After Woo was critically injured while investigating Atlas, Plan convinced M-11 to enlist former teammates Gorilla Man, who got them in to the S.H.I.E.L.D. facility where Woo was being treated, and Grayson, whose alien technology restored Woo to health and youth after the trio broke Woo out. Initially unaware Plan Tzu was watching their every move through M-11's eye, Woo reformed the G-Men to discover the truth behind Atlas. M-11 deduced that Namora, long believed dead, was still alive, and led them to her frozen body, which it revived. After realizing Plan had been manipulating them and ordering M-11 to sever his connection to Plan, Woo led the G-Men to confront their opponent. Plan explained his actions, and ceded control of Atlas to Woo. M-11 currently remains with his former teammates as one of Woo's new Agents of Atlas.