A child's depiction of Ish.
- "If you find my skeleton, please don't step on my skull."
- ―A note from Ish that Joel picked up on a boat
Ish is not physically encountered by Joel and Ellie during the events of the game. Given the presence of Clickers in the areas where these notes are discovered, it is likely that these events happened at least a year or so beforehand.
It is unknown what Ish did for a living before the outbreak. It is most likely that he was a commercial fisherman, as evidenced by his ownership of a good-sized trawler.
Ish was initially out to sea for several months before being forced to go ashore near the Pittsburgh sewer entrance.  He took up residence inside, eventually constructing his own safehouse.  In need of supplies, he searched the nearby suburbs, where he encountered a family, Susan, Kyle and their children, who - much to his surprise - did not shoot him on sight. They traded supplies with each other before Ish returned to his hideout. Ish, lonely and realizing that there was no point in surviving alone, then went back to the family to offer them refuge in the sewers.  The group obliged, and the safehouse eventually became a thriving community. they had a school, makeshift beds, shower stalls, and even rain catchers.  Ish and Danny became the protectors of the community, salvaging, armor, Assault Rifles and sawed off shotguns from dead soldiers. 
At an unknown point in time, a door leading to the safehouse was left open by one of the group, which allowed a horde of infected to flood in. Ish, Susan, and a few of the children managed to escape, barricading the suburb-side entrance to the sewers. Kyle was separated from the group, where he became trapped in a room with a small group of children; the infected at the door. It is implied that he shot all of the children to save them a worse fate, before committing suicide. 
Ish and those who managed to escape with him took shelter in the suburbs, Ish now protecting the last of his group.  His fate, as well as that of Susan's and several children, is currently left unknown.
While Ish is not seen in the game, it is possible to deduce his physical appearance based on details in certain notes. For one, Kyle notes that Ish is skinny when he first trades with them for food. Ish himself also states that he is agile and can sneak easily, explaining why he chose the sewers as a home. A drawing shows him in what appears to be police riot gear, similar to what the The Military currently wears, suggesting that he scavenged a uniform from a dead police officer or a soldier.
Ish originally lived quite near a sewer entrance near where his trawler ran aground. He lived in a small room-like area with a metal door and fence for protection. He seemed to find lots of newspapers, given by how many were stuck on a notice board, when he ventured out for food.
He then expanded it to where Susan's family lived behind the huge lever-activated door. Once he created the small community he made a huge part of the sewers a place to live spanning deep inside. The children even painted the doors at the front to look like a castle.
From what is seen in the game, it seems he permanently moved there and never went back to his original home as it was locked up with no way to get through or he just left it like that when he ventured out one day.
The last recorded place he lived in was in one of the houses in the suburbs shortly after the Infected got in.
- Ish is a reference to the protagonist of the post-apocalyptic novel Earth Abides (1949) by George R. Stewart, whose main character, Isherwood "Ish" Williams, establishes a community of pandemic survivors.
- While in the novel Ish does teach the kids in his community, none of them ever go aboard a ship.
- One of the notes in the sewers is a child's drawing of two people dressed in what appears to be military colors (blue with black vests and boots), armed with rifles. The names "Danny" and "Ish" are written, along with the message "our protectors". This is the first mention of a 'Danny' in this group.
- In the Hebrew language, the word "Ish" means "Person".
- A note from Ish was originally supposed to be found in the mall in Colorado in Left Behind. However Neil Druckmann explained on "IGN: Podcast Beyond" that it was too 'coincidental' and they decided to take it out. One explanation is that it was intended for the players to leave Ish's survival up to their imaginations.
- There is an easter egg on the multiplayer map Beach. At the edge of the cliff next to the riverbank overlooking the Pittsburgh Bridge is a message enscribed on a fence saying "ISH WAS HERE, WISH SOMEONE ELSE WAS TOO"
- Ish, being a sailor, is also a reference to Ishmael, the main character of Moby Dick.