In the original novel, Barlow comes to the town of Jerusalem's Lot in a box shipped overseas by his assistant, Richard Straker. The two then take residence in the Marsten House, an abandoned house considered haunted by the townsfolk. Posing as an antique dealer, Straker kidnaps a local boy, Ralphie Glick, and makes a human sacrifice of the child in an appeasement ritual. Ralphie's brother, Danny, becomes a vampire and begins to infect others, including his mother, Marjorie Glick. Late at night Barlow comes upon unhappy and frustrated Dud Rogers, a hunchbacked dump custodian, laughed at by the young woman he craves, Ruthie Crockett, daughter of businessman and real estate broker Larry Crockett, who signed the real estate contracts with Straker to purchase the Marsten House and the site which will become the antique store front used by Straker. Barlow also comes upon Corey Bryant, a young telephone worker who has been tortured and ordered to leave town by Reggie Sawyer, the man Bryant was cuckolding. Knowing everything that happened Barlow lures Bryant under his hypnotic spell, promising them the spoils, i.e. Ruthie Crockett and Bonnie Sawyer, and drains both men of their blood on the spot.
Danny Glick later pays a night-time visit to one of his schoolmates, Mark Petrie. However, Mark, an intelligent and resourceful child, identifies Glick as a vampire and drives him off with a plastic cross. Mark sneaks into the Marsten House the next day with Susan Norton, intending to kill Barlow. However, they are both captured by Straker; Susan is bitten by Barlow and becomes a vampire, but Mark manages to escape, mortally wounding Straker in the process. Straker is later found hanging upside down, having been drained of his blood by Barlow, who could not resist punishing him. Petrie informs Susan's boyfriend, writer Ben Mears, of Susan's fate, and becomes part of the effort to kill the town's vampires, together with Ben, the Catholic priest Father Callahan, doctor Jimmy Cody and the Lot's high school English teacher, Matt Burke. Susan visits Mark at night, entreating him to let her in as "there are lots more of us now" and promising to "kiss him all over." Mark drives her away, as he had Danny Glick, using the same plastic cross.
When Father Callahan and Mark head over to Mark's parents to explain the danger the family is in, the power is suddenly cut and Barlow appears. He kills Mark's parents by smashing their heads together, but does not infect them. Barlow then takes Mark hostage briefly. Callahan pulls out his cross in an attempt to drive him off, and for a time it works, until Barlow challenges him to throw away the cross. Callahan, not having faith enough to do so, is soon overwhelmed by Barlow, who takes the now-useless cross and snaps it in two, and Callahan is forced by Barlow to drink the vampire's blood.
By now Mark has escaped, part of Barlow's deal with Callahan, and has fled to warn the others. The last we see of Barlow is at the end of the book, when he is killed by Ben Mears and Mark Petrie in the basement of Eva Miller's boarding house.
In Salem's Lot (1979), Barlow was significantly different from his novel counterpart; while Kurt Barlow in the novel resembles an ordinary human being, in the 1979 mini-series, he is depicted with a Nosferatu-like appearance. Interestingly enough, in The Dark Tower, it is mentioned in the beginning that "Type One" vampires (such as Barlow) are horribly disfigured, mutant-like creatures whose teeth grow out so wildly that they cannot close their mouths. Also, this Barlow was never shown to speak, only emitting growls and snarls. Considering his position as a master vampire, it is possible that Barlow was an incredibly potent telepath who had no need for speech.
This version of Barlow has a variety of supernatural powers, such as telekinesis; he opens a locked cell door with a wave of his hand, moves his own coffin along with the crate (which is unnaturally freezing cold to the touch) that it is inside, and causes the Petries' entire house to shake before entering. Unlike other vampires, he is able to enter a person's house without an invitation. Like Count Dracula, Barlow appears to have the ability to be active during daytime; he turns Susan Norton into a vampire after Straker had brought her to him during his daily sleep, though this occurred in the house's basement and was done off-screen. As such, it is never definitively revealed if this incarnation of Barlow could have withstood sunlight. Barlow is played by Reggie Nalder.
In the 2004 miniseries adapted from the novel, Barlow is portrayed by Rutger Hauer. He is a sophisticated, well-dressed older gentleman and, at first glance, his only difference from the rest of the community is his mildly anachronistic appearance (his dress and behavior seem to come from an earlier time). As opposed to the Nosferatu-type creature that Barlow was portrayed as in the 1979 mini-series, this version of Barlow is more akin to the more romantic versions of Count Dracula, although he still has glowing eyes. This portrayal is more in keeping with King's original source novel.
Barlow is described as having a white face with long, sharp, needle-like fangs and red, glowing lurid eyes. And behind him, looming over them, a white, grinning face like something out of a Frazetta painting, which split to reveal long, sharp fangs - and red, lurid eyes like furnace doors to hell. He has long, sensitive fingers, like those of a pianist.