- "I’m proud to be the first Scout troop to achieve this rank. I’m also terrified to be the first Scout troop to achieve this rank. The two emotions are mixing inside my body and it’s confusing. It’s confusing."
Earl claimed he was nineteen years old for decades or more, until suddenly he was a middle-aged adult with a job and family, and no memory how he got to that point. This is reminiscent of pawn shop owner Jackie Fierro, who also spent numerous decades being nineteen years old.
Harlan was one of the leaders of the Night Vale Boy Scouts until the events of Eternal Scouts. While a Boy Scout he ate a human being as part of an exercise, for which he earned the survivalist badge. Once during a Boy Scout training maneuver he met a younger version of himself. 
He is one of the victims of the mute children, who drag him away along with nine others as part of the Eternal Scouts ceremony. Somehow, he survived the mute children, and as of Capital Campaign, he is the sous chef at Tourniquet.
Harlan is somber and self aware of his feelings, and is first mentioned as feeling conflicted between his terror and pride at the upcoming Eternal Scout ceremonies.
He has also struggled with becoming an adult and having a family, mostly due to the fact that he was literally nineteen years old for a long time and from there, suddenly became a middle-aged man with a son. He is often confused by this new life and responsibilities, and he usually consults Cecil about this when he is invited to the show.
At one point his inability to make any decision caused him to start wearing a mask so that no one would recognize him and ask him any questions. In one of the many versions of the divergent timeline, this was the cause of the anomaly. 
- Earl Harlan was Cecil Palmer's childhood best friend. They were in the scouts together and Earl taught Cecil a way to hook his phone up to the radio station while earning their 'Subversive Radio Show Host' badges. When Earl is taken by the scout children, Cecil says that he thinks often about the last moments he spent with him and the things that were said. (What was said was this: "We could have had something, Cecil. Remember that." This implies that there was potential for a romantic relationship between the two of them that Earl seems to have wanted to further pursue at some point.)
- In Homecoming, when Earl first makes a guest appearance on Cecil's show, Earl presses him for information when Cecil brings up a memory of their graduation party together, but Cecil refuses. Earl somberly tells Cecil he thinks they "have something".
- Earl has a son named Roger. After being 19 years old for many years, he woke up one day and discovered he had a family. He does not know his son very well at the beginning, initially saying he does not know his son's name, and forgetting it often even afterwards. He also does not know who Roger's birth mother could be. He later tries to connect with his son by cooking for him and watching football together, with limited success.