* ActingInTheDark: Karim Zreik, co-executive producer of Harpers Island, had the job of informing the actors in this death-laden 2009 Mini Series just when their time was up. The actors, who were not informed ahead of time, gave him the nickname "Karim the Assassin''.
** [[spoiler:Henry's actor wasn't told that Henry was the murderer until episode 8, although he had been told that his character was secretly in love with Abby from episode 1.]]
** Hell, "Karim The Assassin" used to be the original title for the trope.
* DawsonCasting: Weirdly inverted - Katie Cassidy (Trish) is four years younger than her character and Amber Borycki (Beth) is three years younger than hers. Played straight with several of the others though.
** Played doubly straight with Madison, which is one of the reasons her character is so Narmy. She was a twelve-year-old playing a nine-year-old, which wouldn't be so bad if her character ''acted'' nine years old. She comes off more like a twelve-year-old playing a nine-year-old playing a four-year-old.
* EnforcedMethodActing: Even though they knew it was coming, and they did multiple takes of it, when the seagull falls on the bridesmaids table during the first episode, their screams of fear were genuine. No matter how many times you drop a bird on their faces, they never get used to it.
* ExecutiveMeddling: [[spoiler:Madison's InfantImmortality]] aside, the [[http://popminute.com/news/?christopher-gorham-reveals-harpers-island-ending-1121 original ending]] featured [[spoiler:Henry getting away with it. He ends up with Abby and she never knows.]] The writers had to change it because the show needed a happy ending.
* FakeNationality: Averted with Cal, who is played by a British actor. Abby is played by Irish actress Elaine Cassidy.
* WhatCouldHaveBeen: The [[http://popminute.com/news/?christopher-gorham-reveals-harpers-island-ending-1121 original ending]].
** Had the show been renewed for a second season, the plot would have commenced in a new location (sharing only the name 'Harper' in common with the island), with a new mystery and new cast, with some actors returning in new roles. This Anthology format would later be a driving force of the appeal behind other shows like AmericanHorrorStory.
* The actress who plays Abbey is good friends with ColdPlay. She even appears in the end of their music video for ''the scientist''.
* WordOfGod: The night a new episode airs, the actor who got killed off would take part in an online interview with fans, in a Q and A session about the show. Seeing as how none of the actors knew what happens in the show after their characters dies, and they weren't allowed to give away any spoilers, it was mostly just for clearing up misconceptions that were already supposed to be obvious.