- The Geiger counter-esque device used by Peggy to detect the Nitramine is labeled "Property of A(braham) Erskine". The Nitramine is explicitly said to use Vita Ray radiation as a byproduct of its explosion. It's also in a box with a file with pre-serum Steve's photo, which Peggy received at the end of The First Avenger.
- In "A Sin To Err", Peggy breaks out her strong right cross to lay out a male government employee who underestimates her, like she did in The First Avenger.
- The revelation that Dr. Ivchenko is Doctor Faustus, as well as his meeting with Arnim Zola at the end has two major examples: It explains how Zola came upon the brainwashing technology used on Bucky Barnes in Captain America: The Winter Soldier, and it also explains the brainwashing method used by HYDRA in Agents of S.H.I.E.L.D., which Daniel Whitehall refers to as "The Faustus Technique".
- When Hugh Jones asked Peggy her name, she answered "Agent", and in "The Blitzkrieg Button", Agent Thompson says that the most important part of the name of the late Raymond Walter Krzeminski was Agent. In The Avengers Tony Stark joked that Agent Coulson's first name actually was "Agent."
- Howard Stark is mentioned in a newspaper as a "Millionaire, Playboy... Traitor?", similar to Tony Stark's self-description in The Avengers.
- Edwin Jarvis mentions meeting his wife in Budapest, the same location where a Noodle Incident occurred in The Avengers:
- Natasha Romanov: This is just like Budapest all over again.
Clint Barton: You and I remember Budapest very differently.
Continuity Nod / Agent Carter