The scenes with actress Riley Keough in the swimming pool are almost exact recreations of scenes from Marilyn Monroe's last film, Something's Got to Give (1962), which was never completed due to her sudden unexpected death. The footage from that film can be found online.
Dakota Johnson was cast in the lead female role but dropped out due to scheduling conflicts. Riley Keough replaced her.
The film takes place in 2011. The TV news segments shown in the film refer to the date.
The final credits contain a card in code, with the key "b=a" in the bottom right corner. Once decoded, the card reads "a David Robert Mitchell film: Under the Silver Lake"
Sam's favorite Playboy issue is from July 1970, the cover girl is Janet Wolf photographed by Don Ornitz
After Andrew Garfield's character wakes up on the couch after kids vandalized his car, he picks up an Amazing Spider-Man comic book from the table. Andrew Garfield played Spider-Man in The Amazing Spider-Man (2012) movies.
In the apartment of the Comic Man, a selection of life casts is hanging on the walls. They feature next Abraham Lincoln, Johnny Depp (mentioned), Raquel Welch, Grace Kelly and ... Kim Kardashian.
Andrew Garfield and Topher Grace have both appeared in at least one Spider-Man film. Garfield starred as Spider-Man in the Marc Webb series, while Grace starred as Venom in Spider-Man 3 (2007).