Incarnations of the Doctor and The Master from Dr Who appear in this episode - Christopher Eccleston and Eric Roberts respectfully.
This is a flashback episode, giving us some of the backstory to Noah Bennet, including how he came to wear his trademark horn rimmed glasses (his daughter Claire picked them out for him).
Ashley Crow and Matthew John Armstrong are married in real life. They play Sandra Bennett and Ted Sprague respectively. However, They had never shared a scene together until this episode.
In a flashback scene, Claude, played by Christopher Eccleston, says "Happy Father's Day". Coincidentally, during his time on Doctor Who, Eccleston stared in an episode called Father's Day.