Adrian Monk is a former homicide detective working for the San Francisco Police Department (SFPD). He was discharged from his position after his wife, Trudy Monk, was tragically murdered, which led Monk to suffer a mental breakdown. The loss of his wife also severely worsened his obsessive-compulsive disorder (OCD). He is currently employed as a consultant for SFPD.
- Adrian Monk is loosely based on Sherlock Holmes and Hercule Poirot. Monk, therefore, shares his deductive genius with Sherlock Holmes and his obsession with neatness and order with Hercule Poirot.
- Monk is the only character to be in every episode.
- The name "Adrian Monk" consists of 10 letters, which correlates with Monk's favorite number.
- Both his and his brother's name are based on cities in Texas.
- Coincidentally, Jack Monk moved to Texas shortly after leaving their family.
- In Mr. Monk and the Daredevil, Monk mentions he has 312 phobias. However, the continuity of this fact can be disputed as Monk has said different numbers in other episodes. The official list of phobias in this wiki contains around 88 entries.
- With very few exceptions, Monk's OCD is almost never discussed on screen.
- Monk periodically blacks out from time to time, saying and doing things he usually wouldn't, not remembering his actions afterward. (A notable example of this can be seen in the episode Mr. Monk and the Rapper, where he seemingly blacks out, displaying none of his compulsions and accepting a case from the rapper Murderuss, before coming to his senses when the rapper leaves.)
- Monk wears the same thing every day but always in different shades of brown. He is sometimes seen wearing a sweater, too, and also takes off his blazer at home.
- Some of Monk's odd habits include taking 3 showers a day with a star-shaped nozzle, only using 5-watt nightlights, and sleeping only on dark pillowcases (as mentioned in the episode Mr. Monk Goes to the Asylum).
- The only TV channel that Monk watches is Channel 10.
- In Mr. Monk Goes to the Dentist, Monk states that he brushes his teeth 12 times a day and flosses every 90 minutes. He also brushes 40 strokes On each side of his mouth (40 for top left, 40 for top right, 40 for bottom left and 40 for bottom right.) but only after pouring boiling water on the toothbrush.
- Monk only drinks water from the brand "Sierra Springs". This causes him to almost dehydrate in the episode Mr. Monk Goes to Mexico since Monk didn't have access to said brand and he ended up not drinking anything for 36 hours.
- Monk may have an eidetic or photographic memory since he mentions to Dr. Kroger that he actually remembers his own birth.
- According to Mr. Monk and the Airplane, one of his favorite plays is The Music Man.
- Monk was part of the track club in high school but quit after an incident where he bent down to tie his shoe but missed the starting gun as a result.
- Monk plays the clarinet. He even plays it in one episode.
- Although is stated in Mr. Monk Goes to the Asylum that Monk is allergic to tomatoes, yet he can eat one in Mr. Monk on Wheels without a problem.
- In total, Monk has been arrested three times over the course of the series. The first time was when he walked into someone else's house, mistaking it for his, in Mr. Monk Goes to the Asylum. The second time, he was framed for the murder of Frank Nunn, Trudy's murderer, in Mr. Monk Is on the Run (Part 1), and the final time was when he was arrested for obstruction of investigation in Mr. Monk Gets Stuck in Traffic.
- Monk has been institutionalized at least once.
- In the episode Mr. Monk Meets His Dad, Monk is heard saying "After 39 years...", indicating that Monk is 47 years old since the last time he saw his father was when he was 8.
- According to the episode "Mr. Monk and the Big Game", Monk has solved 105 murders since the start of his career.
- In "Mr. Monk and the Class Reunion", it is revealed that Monk was nicknamed "Captain Cool" in college. When Natalie mentions the name "Captain Cool" to a couple going to the reunion, she learns that Monk earned the nickname because he spent every weekend defrosting his refrigerator.
- In Mr. Monk and the Kid, Monk bonds with a toddler named Tommy and almost adopts him but decides not to upon realizing that his mental health issues make him incapable of providing proper care for the child.
- Similarly, Monk has a hallucinatory vision of Trudy in Mr. Monk vs. The Cobra, in which she says that they should've had children together.
- Monk does not drink alcohol since he becomes drunk after taking only a single sip.
- In Mr. Monk Gets Drunk, however, he does drink some of Trudy's favorite wine for their anniversary and also consumes an entire bottle of wine later in the episode to gather information from one of the suspects, Nicoletto. Although it should be mentioned that he drinks the entire bottle thinking that it was nonalcoholic wine.
- Monk is extremely reluctant to talk about sex or anything related to that topic, especially if it regards his own sex life with his wife.
- Monk is not a combatant but in a few episodes he demonstrates skillful self defence when his friends are in danger.