This article contains brief mentions of suicide.

actors from the Monk cast.

Bagley’s role as Detective Adrian Monk’s arch-enemy – fellow obsessive-compulsive patient Harold Krenshaw – was intended to be a one-off cameo, but his comedic chemistry with Tony Shalhoub led the character of Harold to become a staple in the dramedy police procedural Monk. Despite, or perhaps because of their many shared obsessive compulsions and quirks, Harold and Monk developed a heated rivalry from their first encounter, and this petty animosity became one of the best running jokes on Monk.

10 Mr. Monk’s Last Case: A Monk Movie

Harold Is Not Forgotten

While not a Harold Krenshaw appearance per se, Mr. Monk’s Last Case: A Monk Movie (2023) does contain a reference to this serialized Monk character, driving home Tim Bagley’s absence from the film. During one of the Monk’s letter to Harold Krenshaw in Mr. Monk’s Last Case is the only one whose contents are revealed. In his goodbye, Monk reassures his old arch-enemy that “almost everything has been forgiven.”

In light of the way that Harold and Adrian parted ways during Bagley’s final appearance in the series – which occurs in season 8, episode 8, “Mr. Monk Goes to Group Therapy” – Adrian’s note to Harold in the Monk movie begs the question of whether the two have seen each other since that point. The fact that it was the only note to be revealed to the viewer also hints that Bagley could return in a Mr. Monk’s Last Case: A Monk Movie sequel.

9 Season 7 Episode 16, “Mr. Monk Fights City Hall”

Harold Casts His Vote

In “Mr. Monk Fights City Hall,” Monk and Harold’s rivalry continues as Adrian Monk tries to prevent the demolition of the parking garage where Trudy was murdered. Although the city of San Francisco planned to turn the garage into a community park and playground, Adrian resisted the change. The garage was not only an emotional landmark for Adrian, but he also believed it could answer important questions about his wife Trudy Monk’s death.

Of course, Harold had little empathy for Adrian’s situation and used his position in City Hall to vote against Monk’s motion twice in a row. Throughout their battle over the demolition of the garage, Harold attempted to leverage his position to obtain a key piece of information from Mr. Monk: the name of Adrian Monk’s new therapist. His refusal to reveal Dr. Bell's identity only fueled Harold’s spiteful behavior towards him. This jealousy and the need to have everything Adrian has (and better) is classic Harold Krenshaw.

8 Season 3 Episode 15, “Mr. Monk and the Election”

Harold Fights Natalie

In “Mr. Monk and the Election,” Harold decides to run for a position on the school board – in direct opposition to Natalie Teeger (Traylor Howard). Harold defeats Natalie, winning the election to the board with a significant lead, but not before Monk goes toe-to-toe with Harold in a highly personal – and highly public – debate.

As per usual, Harold weaponizes his relationship with Dr. Kroger to get under Adrian’s skin, bragging that he has been invited for meals at their therapist’s home, and even introduced Charles Kroger to his fiancé – of whom Adrian was unaware. This is one of three episodes in which Monk expresses a desire for Harold to be responsible for a murder, the other two being “Mr. Monk Gets a New Shrink” and “Mr. Monk Goes to Group Therapy.” Notably, this episode features a young Nick Offerman as one of the many well-known Monk guest stars.

7 Season 7 Episode 7, “Mr. Monk’s 100th Case”

Harold Puts In His Two Cents

In a 60 Minutes-style TV special celebrating famed detective Adrian Monk’s achievements as he takes on his 100th case, Monk's “fellow OCD patient” Harold Krenshaw is featured as an interview subject. Of course, Harold immediately takes the opportunity to put down his arch-nemesis, pointing out that Adrian is still on his 99th case and bragging that his new therapist is much better than Monk’s. Ironically, Harold demands the name of Monk’s therapist just nine episodes later in “Mr. Monk Fights City Hall.”

The character of Harold Krenshaw was supposed to be a one-off, but became a serialized character after Tim Bagley and Tony Shalhoub hit it off during the filming of "Mr. Monk and the Girl Who Cried Wolf."

This episode broke the Monk formula with an interview-style montage layered atop the events of the episode, allowing various ing characters to offer somewhat meta-commentary on the life of Adrian Monk. It is also the only solo appearance of Harold Krenshaw’s character; every other Monk episode featuring Tim Bagley has the character of Harold appear during a direct interaction with Monk.

6 Season 8 Episode 8, “Mr. Monk Goes to Group Therapy”

Harold Delivers the “Here’s What Happened”

After a change in their health insurance plans renders Dr. Bell’s patients unable to see him privately, Neven begins a group therapy session and invites a begrudging Monk to . Despite his trepidation, Adrian attends a session and is horrified to find his longtime enemy Harold Krenshaw is present. Soon after, patients from the group begin to die under mysterious circumstances. The way Harold greets Monk in front of Dr. Bell is a perfect summary of their dynamic: “I’m glad you’re here, and I don’t feel threatened in the slightest.”

This episode notably turns Monk’s usual suspicion of Krenshaw on its head, with Harold instead accusing Monk of being the murderer, claiming he was the only one who had motivation and know-how. “Mr. Monk Goes to Group Therapy” also changes up the classic Monk “here’s what happened,” with Harold delivering this Hercule Poirot-style summation of whodunnit – one of only two times in the show that Monk was not the one to deliver the spiel.

5 Season 7 Episode 8, “Mr. Monk Gets Hypnotized”

Harold Goes To Nudie Town

After running into an elated Harold Krenshaw in “Mr. Monk Gets Hypnotized,” Mr. Monk decides to take Harold’s recommendation of the fellow OCD patient's new therapist. Monk hopes that hypnotherapy will render him equally “cured” of his OCD. Unfortunately, this form of therapy instead leads Adrian to experience regression into a childlike state, interfering with the investigation of a case. In his regressed state, Adrian climbs trees and catches frogs, acting out the childhood he wished he could have had.

Harold’s hypnotherapy later backfires on him, as well, leading Monk’s quirky arch-enemy into an uncharacteristically euphoric state that causes him to streak through San Francisco and eventually be arrested for public indecency in one of the funniest Monk scenes. Luckily, this is the straw that breaks the camel’s back for Monk, who decides to abandon his hypnotherapy and return to the care of Dr. Neven Bell.

4 Season 6 Episode 7, “Mr. Monk and the Daredevil”

Harold Is The Frisco Fly

In “Mr. Monk and the Daredevil,” Adrian is taken aback when he discovers that his nemesis Harold Krenshaw has an alter ego: the famed San Francisco daredevil, the “Frisco Fly.” Knowing Harold is even more petrified of heights than he is, Monk sets out to prove that Harold is lying. Along the way, Adrian inadvertently uncovers a plot against Krenshaw’s life.

Monk and Adrian’s dynamic is perfectly encapsulated in this episode: Harold will do anything to get under Adrian’s skin and step into the spotlight. Likewise, Adrian tirelessly seeks to discredit Harold, envious of the attention he receives as well as his perceived progress in managing his obsessive compulsions. Monk even posits that Harold never fell off the roof despite his injuries; he instead theorizes that a dummy was thrown down as Harold waited below to receive his accolades.

3 Season 3 Episode 6, “Mr. Monk and the Girl Who Cried Wolf”

Harold Is Wrong

In “Mr. Monk and the Girl Who Cried Wolf,” Monk’s assistant, Sharona (Bitty Schram) begins seeing apparitions of a dead man and seeks out treatment under the care of Monk’s therapist, Dr. Kroger (Stanley Kamel). When he accompanies Sharona to her first session, Monk meets Harold Krenshaw for the first time in Dr. Kroger’s waiting room. Adrian’s comical introduction to Harold in this episode sets the stage for their series-long rivalry.

Although the two initially bond over their shared hatred for Dr. Kroger’s new white noise machine (which is half a decibel louder) they soon find themselves bickering over how to organize the magazines on display in their therapist’s office. Harold and Monk’s heated debate over whose method is correct is the perfect example of how their obsessive compulsions clash; ultimately, these two hate one another simply because they are too similar.

2 Season 5 Episode 7, "Mr. Monk Gets a New Shrink"

Harold Finally Wins

In “Mr. Monk Gets a New Shrink,” Monk and Harold are both thrown into disarray by Dr. Charles Kroger’s abrupt retirement following the murder of his cleaner, for whose death he feels responsible. Struggling to cope with the change and find a new therapist, Adrian investigates the case and soon finds himself staking out Dr. Kroger’s house at the same time as Harold.

Dr. Kroger: Relax, Harold. Just take it easy. You'll be okay. We're gonna get a doctor. We'll get a doctor.

Adrian Monk: How's he doing?

Dr. Kroger: He's gonna be okay. Did you see what he did? He took a bullet for me, Adrian.

Harold Krenshaw: Monk. Monk. Come here. Closer. [whispers] Beat that.

Luckily for Dr. Kroger, his patients’ obsession with him pays off when both he and Monk are kidnapped by the killer. In what is arguably the peak of Monk and Harold’s rivalry, Harold winds up taking a bullet for Dr. Kroger before gloating to Monk, “Beat that!” Unfortunately, this episode foreshadowed Dr. Kroger’s replacement on Monk following the real-life death of Monk actor Stanley Kamel, who ed shortly before filming could begin for season 7.

1 Season 8 Episode 4, "Mr. Monk is Someone Else"

Harold Blows Monk's Cover

In one of the best Monk episodes, “Mr. Monk is Someone Else,” Adrian’s investigation of a case requires Monk to pose as a mobster. Unfortunately, the timing of Harold Krenshaw’s very inconvenient vacation to Los Angeles just so happens to coincide with that of Monk’s covert mission, and he soon arrives to blow Adrian’s already fraying cover.

“I will say one experience I had, and I never really talk about this, but when I worked with Tony Shalhoub on Monk…it was my first episode on the show and I was only supposed to guest star once. He just made me feel like a million bucks, like I was just gold. We improvised a little and I could see him laughing and to see him laughing meant so much to me. And they kept calling me back for more episodes and every time we had a scene together Tony would say ”Can we improvise a little here?” And I found out later that there really was no other improvisation in that show; I think he just enjoyed our playful exchange. What I took away from that was how he made me feel. He made me feel like I was an extraordinary actor and I just think it’s so important that when we play with people we make sure that they know we appreciate what they’re doing. Tony is such a classy man and just a brilliant actor. He was constantly surprising me, and it would make me step up to his level and try to surprise him. It was thrilling to play a scene with him. But again, the big takeaway was just the way that he treated me. It meant everything to me. And I just always think about that when I’m working with other actors now.” -Tim Bagley, via Acting Studio Chicago

As the undercover detective confers with his partners in crime, Harold glides up to Monk’s table on rollerskates. In true Krenshaw fashion in Monk, he begins repeatedly and loudly calling Adrian’s name until Monk is forced to acknowledge him and claim he has the wrong guy. This scene is by far the funniest Harold and Monk interaction in the entire series, with Monk not only threatening his nemesis in a stereotypical “mobster” voice but also comically rolling Harold away on his skates. It sums up everything that is so annoying about Krenshaw, putting it at the top of the list.

Source: Acting Studio Chicago