The Finn is a fence for stolen goods and one of Molly's old friends. He provides a variety of debugging and sensor gear, and aids several lead characters in Gibson's works. He appears in the short story "Burning Chrome" (1982); "Neuromancer" (1984); "Count Zero" (1986); and arguably "Mona Lisa Overdrive" (1988). He is arguably the one character to appear in all three installments of the Sprawl trilogy.

In "Burning Chrome," the Finn provides goods for the protagonists Automatic Jack and Bobby Quine. He appears only once, and seems more friendly and jovial than in any other depiction.

"Neuromancer" is perhaps the Finn's most memorable appearance. Here, he assists Case and Molly in unraveling the mystery of their employer, Armitage. It is with the Finn's help that Molly and Case discover that they are working for an A.I. named Wintermute. Later in the book, Wintermute uses the Finn's personality to communicate with Case and Molly in the Matrix (as Wintermute chooses its appearance based on its subjects' memories).

The Finn returns in "Count Zero," more cynical, unfriendly, and threatening than ever before. Here, he proves that he is capable of defending himself, killing three would-be assassins with his "dog food trick." Though he helps the main characters once again, he expresses none of the friendship that he showed to Bobby Quine, Automatic Jack, Molly or Case, instead regarding them with contempt and suspicion.

By the events of "Mona Lisa Overdrive," the Finn has passed away. (The cause of death is not given, but since he is described as being very old even in "Burning Chrome," it is likely that he simply died of old age.) The Finn's old shop is now ruled by an A.I. construct based on his personality, created by the Finn himself before his death. His reason for doing this is never revealed. (It is plausible that he was inspired to do so after learning that Wintermute used his identity; but since it's never stated whether the Finn did in fact learn of that, it cannot be confirmed.)

The Finn is an antisocial man, and his personality seems to degrade over time, becoming less friendly in each book or story. He always lives alone, and is described as having agoraphobia (fear of being out in the open). His closest friendship seems to be with Molly, who he often calls "Sweet Meat." (It is highly doubtful that any other business associate could get away with calling her this.) Despite his aloofness, the Finn still manages to keep up with news about where his former friends and associates have been (for example, informing Molly years after "Neuromancer" that Case is now married with four children). His age is never given, but he is implied to be quite old; on two separate occasions he has told someone, "I have a pair of shoes older than you" ("Burning Chrome" and "Count Zero.") He usually wears a tweed suit, that is often stained from sloppy eating, and enjoys Partaga cigars.