John Clark Jr.

John Clark Jr. is a fictional character in the television series NYPD Blue. He was played by Mark-Paul Gosselaar for four years, from season 9 until the end of the series.

Clark Jr. was partnered with the rough but friendly detective Andy Sipowicz after Sipowicz's previous partner, Danny Sorenson, was murdered in an undercover sting gone bad. Clark earned his detective badge after courageous action in an undercover operation.

Sipowicz became a kind of mentor for the young detective, and much of the veteran detective's skill rubbed off on Clark.

His father, Clark Sr., was a by-the-book but not very competent detective who disapproved of his son's choice of precinct. He referred to the 15th Precinct as a "hellhole" and held a strong dislike for Sipowicz, whom he knew from previous experiences (their main clash came years earlier when Clark Sr. ruined a case where Andy got a confession by not emphasizing the suspect's Miranda rights in textbook fashion, and the suspect later went out and killed an elderly woman). The conflict between father and son came to a pinnacle when Clark Sr. threw John out of the house due to his decision to work at the 15th, rather than choosing his father's precinct. Clark Sr. further disrupted his son's career when he showed up drunk at the 15th Precinct, having been forced into retirement because he had been involved with a prostitute who was murdered (by her pimp) and then being turned into an IAB informant, and demonstrating his alcoholism for all of the squad to see. Later, he nearly let his son's career be ruined over his own behavior, before Sipowicz pressed him to clear John Jr.'s name.

Tragedy later struck when John's father had to quit the police force, and later committed suicide, over an IAB trial. Around the same time, John's bipolar ex-girlfriend, Dr. Jennifer Devlin, died of a prescription drug overdose. Following these traumas, John experienced a brief but ugly period where he was often drunk and had a number of indiscriminate sexual encounters, causing at least one of the squad's cases to be ruined in court. However, with Sipowicz's help, Clark cleaned up his act, and he soon began dating Assistant District Attorney Laurie Munson.

Despite these troubles and some early mistakes in his career, Clark Jr. soon developed an excellent interview manner and attitude, which even Sipowicz noted after observing an interview conducted solely by Clark. Clark eventually became the 15th Squad's lead detective, partnering with Baldwin Jones, after Sipowicz was promoted to Sergeant at the series's conclusion.