- Billing Displacement: The trailer and (especially) posters for the film prominently feature Michelle Williams, who plays Lee's ex-wife Randi. Her performance is very good and her character is important in a narrative sense in establishing elements of Lee's background but her entire screentime adds up to less than ten minutes.
- Career Resurrection: Casey Affleck's buzz died down substantially for nearly ten years after the acclaim he received for The Assassination of Jesse James by the Coward Robert Ford and Gone Baby Gone, making some worried that he was back to being Luigi Affleck. Manchester opened to universal acclaim, and for his portrayal of Lee, Affleck has been nominated for (and won) nearly every critical and guild award, up to and including the Academy Award for Best Actor, cementing his acclaim in film history.
- Cast the Expert: Kevin Grondin, who plays the funeral director, is also one in real life.
- The Danza: Kyle Chandler playing a character named Joe Chandler.
- Throw It In!:
- The EMTs' struggle with getting Randi's stretcher into the ambulance was unscripted, but the director left it in as it fit the atmosphere of the scene.
- Surprising everyone on set, Casey unexpectedly cried during the scene in the morgue. The brutal, yet beautiful scene had been written without it, but the director decided to keep the scene.
- What Could Have Been:
- Matt Damon was originally set to direct and star in the movie, but scheduling conflicts with The Martian led him to drop out (while remaining on as Producer), asking writer Kenneth Lonergan if he could step on to direct, and recommend Casey Affleck for the lead, whom he later admitted was a much better choice for the part.
- There was going to be a scene of the family seeing a whale do a spectacular jump, representing a last moment of joy before everything goes to hell. Unfortunately, they ran out of money for it, and Damon has lamented the scene was what really held the whole story together in the script.
Trivia / Manchester by the Sea