- Clark Gregg is the father of Stella Frances Gregg. He previously worked with her in Trust Me.
- Clark Gregg voiced alternate versions of Phil Coulson in Ultimate Spider-Man, Lego Marvel Super Heroes, Marvel Heroes and Lego Marvel's Avengers.
- Clark Gregg worked again with Joss Whedon in Much Ado About Nothing.
- Clark Gregg previously worked with Amy Acker in Much Ado About Nothing, and personally asked her to take the role of Audrey Nathan.
- Clark Gregg previously worked with Spencer Treat Clark in Much Ado About Nothing.
- Clark Gregg previously worked with Wilmer Calderon in The Shield.
- Clark Gregg previously worked with Tim DeKay, Blair Underwood and Constance Zimmer in The New Adventures of Old Christine.
- Clark Gregg is one of the actors to portray characters for both Marvel Studios and Lucasfilm, both of which are owned by Walt Disney Pictures. He portrayed Dickinson in The Young Indiana Jones Chronicles.
- Clark Gregg is the first actor in the Marvel Cinematic Universe that appears as the main cast of a television series Agents of S.H.I.E.L.D. who previously appeared in films Iron Man, Iron Man 2, Thor and The Avengers.
- He won a Saturn Award for Best Supporting Actor for his work on The Avengers.