The film was promoted at the 2010 San Diego Comic-Con International during which a teaser trailer narrated by Samuel L. Jackson was shown followed by an introduction of the cast. In June 2011, Marvel Studios announced it would not be holding a panel in Hall H at the 2011 San Diego Comic-Con International despite expectations. With filming still in production, studio leaders decided that, as far as Hall H goes, it wasn’t prepared to compete with its own past and wild fan expectations.

In July 2011, a teaser trailer that was meant to be the post-credits kicker of Captain America: The First Avenger was leaked online. Sources within Disney and Marvel would not confirm where the footage came from, however Anthony Breznican of Entertainment Weekly speculated that it came from a preview screening and described the footage as “shaky, fuzzy, flickering and obviously filmed on a cell phone.