He is something of an underground mercenary, hired by everyday people to fix situations that cannot be dealt with through legal means (e.g. by blackmail).
Jack adamantly refuses to take murder for hire jobs and almost never becomes involved in cases involving domestic issues between couples, kidnappings or missing persons as he believes officialdom, Jack's personal name for society norms such as the police, is the best option in those situations given their superior resources.
All of Jack's fix-its are immediately relevant problems in today's world, covering topics such as conspiracy groups, grassroots movements, designer drugs, public shootings, terrorists, legal dealings, and scientific and biological experiments.
Jack is a man who carefully keeps himself outside of what he terms "officialdom", refusing to enter the workforce (and claims to have no U.S. Social Security number).
Jack has also shown himself to be a capable actor, having successfully portrayed himself in various roles during his fix-it jobs such as an upscale realtor, a reclusive multi-millionaire and a lowlife thug.
Jack is prone to fits of righteous anger in which he will dive into situations rashly, though luck, skill and creative improvisation usually serve him well.
Jack prefers to handle his fix-its with cunning and finesse with how he fulfils his customer's request as a matter of personal pride.
A vandal continually destroyed his neighbor's lawn with his car, and he offered his services not only in repairing the damage, but ensuring that it would not recur.
This compelled Jack to perform his first self-employed fix-it; investigating the murder after police dismissed the crime as unsolvable.
He dropped out and left "officialdom", entering his underground lifestyle in New York where he almost completely severs ties with family and friends, except for very rare telephone calls and even rarer personal visits to his father.
Typically, Jack gets involved in multiple fix-its in each novel, usually one of those turning into a large issue that leads him to use his skills to battle supernatural forces.
As the series progresses, the appearance of supernatural beings and situations lead Jack to become entangled in a larger, universal fight.
While he protests his involvement, he is dragged deeper with each novel into growing unrest and chaos—the observable effects of a cosmic battle for all existence.
The Otherness (and its agents) derive sustenance from destruction and thus finds sentient life useful as it can be guided to destroy its surroundings and itself—like self-slaughtering cattle.
This imprisonment came to an end during the events of The Keep; Rasalom was (seemingly) destroyed along with the sword and Glaeken began to age as a human.
Shortly thereafter, a pair of superhuman beings known as "The Twins" (responsible for the worldwide sightings of men in black) took leadership over the Yeniçeri.
The phrase, "a spear has no branches" is applied to him often, as the Ally attempts to hone him into a lone, hardened warrior by killing those he has emotional attachments to.
Several novels in, it is revealed that a third force in the power struggle has been making its presence known through various representatives: The Lady, seemingly a series of different women with nothing in common save strange canine companions and oracular knowledge.
This trilogy finally puts in print Wilson's stated connection between his supernatural and science fiction via the character of Jack's "Uncle Gurney", the protagonist of his drug-war satire short story "Lipidleggin'", and the ancestor of far-future economic revolutionary Peter LaNague.
Wilson, in early 2011, signed a contract to write an additional Repairman Jack trilogy after the completion of the main story arc with The Dark at the End and the heavily revised Nightworld.