Jake Doyle (main character): went to juvie as a child. regularly breaks into houses and cars. regularly gets into fights (although i'd argue doesn't regularly start them). regularly gets arrested.
Malachy Doyle (his father): regularly does the exact same things. teaches those things to everyone else in the family. literally once helped a friend fake his death so he could commit insurance fraud and escape to Iceland, that was just a whole episode.
Kathleen Doyle (his sister): introduced as on the run from criminals that she stole from after working for them. does recreational drugs, but that's like the chillest thing on this list, I only mention because it is framed as An Illegal Thing She Does.
Christian Doyle (his brother): former fixer. addict who's trying to get clean. for awhile on the run from the law because of presumed murder that he does not remember whether or not he committed. later gets married to a former criminal as well. did steal money from his own brother also.
Tinny Doyle (his niece/Kathleen's daughter): for awhile runs a weed growing farm. regularly breaks the law as a police officer in order to help out her family. (listen my dream is that she also quits the force and becomes a P.I. like her family before her but that's an aside). arguably the least criminal, but has done so many minor criminal things.
Rose Miller (Malachy's gf/wife): former career criminal. her mother was literally a grifter and still is. taught Rose everything she knows. her ex husband went to jail for a crime they both committed. her ex husband also regularly shows up to pull the rest of the family into crime shenanigans.
Des Courtney (Tinny's bf): introduced committing petty crimes. is then actively taught by the Doyle family how to break into places. his father was a career bank robber who's currently serving time.
Kevin Crocker (Jake's ex partner/Kathleen's ex boyfriend/Tinny's father): former addict and corrupt cop, went on the run for a murder he didn't commit and then did a bunch more crime to get by and maybe also for fun.
Sloan Daniels (Jake's sort-of-kid-it's-complicated): budding career criminal after having been in foster care for most of her life. rips off a mobster and steals all the family money (she feels very bad afterwards though, they make up. i do not think they get the money back though).
Not to mention their family in Ireland who are also career criminals. and the vast amount of friends and acquaintances who also do varieties of crimes.
Leslie Bennett (Jake's on and off again girlfriend and a cop): pls. it's very hard to Not Notice What You Are Doing.