Milestone: First partnership with Peggy Carter, becoming her off-book field ally.
Edwin Jarvis makes his entrance materializing in a dark alley to see Peggy Carter off to his employer without so much as an introduction. It does not go well. That employer, however, is discovered to be Howard Stark, fugitive from Congress. Jarvis is the unflappable man who keeps his household running. He guards his evenings with the seriousness of a state secret: sherry at seven, Benny Goodman at eight, bed at nine, and a wife named Anna who must never know what her husband gets up to after dark. When Peggy sizes him up as new to espionage, he counters that he once caught the cook pocketing the good spoons, which he clearly considers ample credentials.
Jarvis proves startlingly useful. When a stolen Nitramene device begins to glow orange in Peggy's hands, he talks her through neutralizing it over the phone, rattling off blast radii and the precise chemistry to render it inert without even the slightest tremor in his voice. He reads her war record and tells her plainly that the men in her office are fools for not seeing what she is. When the Roxxon mission begins to go sideways, he doesn't hesitate when Peggy tells him to get the car to her immediately. He wheels the getaway car expertly, narrowly avoiding a tragic end for both he and his new partner. The man who insists he is merely a butler is easily the most capable person Peggy has on her side, and he manages to pull it off while feeding his wife cover stories about extracting Stark's amorous admirers from penthouses.