Descriptions extracted and slightly modified from the article on Trainspotting the novel on Wikipedia.
Mark Renton a.k.a. Rents / Rent Boy
- Ewan McGregor
Narrator and main character in the film. Renton is the voice of (relative) sanity among his group of friends, many of whom he can't stand. He narrates his daily life. He is capable of fitting in well enough to common society, but uses heroin as a means to withdraw.
Daniel Murphy a.k.a. Spud
- Ewen Bremner
Naive and childlike, Spud is both the whipping boy and only real source of comfort among his circle of friends; they feel genuinely protective of him, even as they repeatedly mock and take advantage of him.
Simon Williamson a.k.a. Sick Boy
- Jonny Lee Miller
A slick, amoral and seductive, Scots-Italian, con artist, and Renton's oldest friend. He is always on the lookout for the "perfect score", despite being perfectly inept at serious crime.
Francis Begbie
- Robert Carlyle
A violent sociopath, Begbie terrorizes his "friends" into going along with whatever he says, assaulting and brutalizing anyone who angers him. He is the only one in the group who does not use heroin, considering addicts to be the lowest form of life.
Tommy MacKenzie
- Kevin McKidd
A friend of Renton's, Tommy does not use heroin until his girlfriend dumps him. He seeks to numb the depression by experimenting with the drug. His resulting addiction weighs on Renton's conscience, and in part provokes him to seriously attempt sobriety.
Dianne Coulston
- Kelly MacDonald