Before the events of the novel, it is suggested that Barlow's original name or alias was Breichen and that he was an Austrian nobleman. As Breichen, Barlow corresponded for twelve years with Hubert "Hubie" Marsten, a former Depression-era hitman living in Jerusalem's Lot, Maine. Marsten murdered his wife and committed suicide, but not before burning his letters with Barlow. The novel strongly implies that Marsten entered into an agreement with Barlow that allowed him to eventually come to Jerusalem's Lot.
In 1975, Barlow arrives the town of Jerusalem's Lot in a box shipped overseas by his human assistant, Richard Straker The two take residence in Marsten's abandoned mansion, considered haunted by the townsfolk. Barlow and Straker pose as antiques dealers and open a shop in the town; Straker tends to the shop and handles business arrangements while Barlow is seldom seen in public. 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 other locals.
Barlow makes his first appearance in the book when he encounters Dud Rogers, a hunchbacked dump custodian. 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 their desires, Barlow claims Rogers and Bryant as his first victims.
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. 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. In the end of the book, Barlow is killed by Ben Mears and Mark Petrie in the basement of Eva Miller's boarding house.
In the Dark Tower series, it is revealed that Barlow is a type one vampire, capable of hibernating for centuries and is highly intelligent and cunning. However, seems to appear more human than the other type one vampires.
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 monstrous (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.
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.
1995 radio drama
In the 1995 BBC radio dramatization of 'Salem's Lot, Barlow was voiced by Doug Bradley.
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 portrayal is more in keeping with King's original source novel.