Maya Forbes' sister, China Forbes, performs the song "The Northern Line" over the end credits, a song for which she also composed and wrote the lyrics.
The film takes place in 1978.
The name of this film, Infinitely Polar Bear (2014), comes from one of the daughter's of Cam Stuart, Mark Ruffalo's character, mispronouncing the bipolar condition her father has.
Mark Ruffalo and Zoe Saldaña appeared in the Marvel Cinematic Universe as Bruce Banner/The Incredible Hulk and Gamora respectively. They would both go on to appear together as those characters in Avengers: Infinity War (2018) and Avengers: Endgame (2019).