Leonard W. "Lennie" Briscoe was a fictional character on NBC's long running crime drama, Law & Order. He was featured on the show for 12 seasons, from 1992 to 2004. He was created by Walon Green and Rene Balcer, and was portrayed by Jerry Orbach. He also appeared in all three Law & Order spin-offs, and was part of the original cast of , appearing in only the first two episodes due to Orbach's death.
Lennie Briscoe is introduced in the episode "Point of View" as the new senior detective in the Homicide Department of the New York City Police Department's 27th Precinct. His boss during his first season on the show is Capt. Don Cragen (Dann Florek); a year later, Lt. Anita Van Buren (S. Epatha Merkerson) takes over the homicide squad. He was previously assigned as a detective in the 116th Precinct in Queens.
Logan is transferred in the 1995 episode "Pride" to the Domestic Dispute Department in Staten Island for slugging a politician who had just gotten off on a murder charge (based on the Dan White case), and is replaced by Det. Rey Curtis (Benjamin Bratt). Four years later, Curtis goes into early retirement to take care of his Multiple Sclerosis-stricken wife, and he is replaced by Det. Ed Green (Jesse L. Martin) in 1999.
Orbach portrayed a defense attorney in the second season episode "The Wages of Love" before assuming the role of Briscoe.
He was born on January 2, 1940. A veteran of two failed marriages, Briscoe has two daughters, Cathy and Julia, and a nephew, Det. Ken Briscoe (played by Orbach's son, Chris). His family is fairly dysfunctional, however; an alcoholic for much of his life (he becomes sober in late middle age), he was often absent from his daughters' lives, and they have distant, fractious relationships with him as adults. Briscoe blames himself, especially when Cathy, a methamphetamine addict, is murdered by a drug dealer after she testifies against the dealer in court. However, he finds closure when the drug dealer dies from a heroin overdose.
In the 1996 episode "Aftershock", after witnessing an execution from a case he helped investigate, Briscoe falls off the wagon with disastrous results; A.D.A. Claire Kincaid (Jill Hennessy) is struck and killed by a drunk driver while driving him home from a bar. The experience shakes him deeply, and he remains sober for the rest of his life.
Briscoe was raised Catholic, but is Jewish on his father's side and occasionally attends Jewish services as a courtesy to his first wife. It was revealed that his father suffered from Alzheimer's. Though not actually Jewish according to the traditional definition, Briscoe is sometimes the target of antisemitism from criminals and even some of his own colleagues. Briscoe also develops a friendship with the only other featured Jewish police officer during his tenure, Det. John Munch (Richard Belzer), despite Munch's initial resentment when he discovers Briscoe had slept with one of Munch's ex-wives.
Briscoe is one of many characters on the show to have served in the military; he was at one point a corporal in the United States Army. On several occasions he has referred to his service in the Vietnam War. After leaving the Army, Briscoe joined the NYPD in the 29th Precinct and walked a beat there with stops at the 31st, 33rd, 110th, and 116th Precincts before rising to the rank of Detective. Upon joining the NYPD, Briscoe's badge number is '8220'.
One of Briscoe's former partners, Det. John Flynn (Kevin Conway), falsely implicates him in the 1996 episode "Corruption" of taking seized drugs from the 116th Precinct evidence room (given to him by Flynn) during their stint there several years before. Flynn makes this allegation partly to throw off the Hellman Commission, which had been convened to investigate police corruption, including the questionable shooting death of a suspect by Flynn himself, and partly as revenge against Curtis, who refused to falsely defend Flynn. Briscoe, however, has an alibi for the time he was allegedly receiving stolen drugs from Flynn - he was having an affair with Officer Betty Abrams, a married woman. Against Briscoe's wishes, Abrams testifies before the commission to exonerate him. Because of the affair, however, the commissioners question her credibility. Although Briscoe is ultimately cleared, defense attorneys of suspects he subsequently arrests exploit the allegations through the rest of his career.   
There are moments in Briscoe's career where his decisions are controversial. In the episode "Stalker", a stalker accused of murdering a woman could have gone free because the victim confessed to lying to the police about one of his earlier attacks. However, after the victim is found murdered, Briscoe goes to McCoy and tells him that he now believes that the victim did not lie to the police of the stalker's earlier attacks and that he is willing to take the stand and state that the original police report was incorrect. Curtis would be called by the defense to testify that the original police report was correct in his opinion. At the end of the episode, the stalker is found guilty; outside the courtroom, Curtis and Briscoe reconcile.
Shortly after Green is assigned as his partner, he and Briscoe nearly come to blows during a particularly difficult investigation of a robbery/homicide. Their primary suspect confesses as he is being arrested, but because Briscoe is the only officer within earshot, Green, Van Buren, and McCoy are placed in a difficult position with regard to the confession. Again, Briscoe is, in the end, vindicated, and he and Green work to rebuild their professional rapport and what eventually ends up as a close friendship.
On the first season of , Briscoe makes three guest appearances assisting his old boss Cragen. (His detective nephew is briefly seen in the episode "...Or Just Look Like One"). Briscoe also makes a guest appearance in the episode "Poison," in which he assists the Major Case Squad on a similar case.
Soon after leaving Law & Order, the Briscoe character appeared in Law & Order: Trial By Jury, in which he becomes a District Attorney Investigator with partner Hector Salazar (Kirk Acevedo) for D.A. Arthur Branch (Fred Thompson).
In 2005, the Briscoe character was written out without being killed off, coinciding with Orbach's death in December 2004 from prostate cancer. In a 2007 episode of Criminal Intent, Logan says that Briscoe has died but he still sees him alive in his dreams. In 2008, Green explains he returned to gambling briefly after Briscoe died. In a 2008 episode of Criminal Intent, a Catholic priest who was a friend of Briscoe approaches Logan after a prisoner's deathbed confession to a 16-year-old double murder in the Bronx. This episode proved to be Noth's final appearance as Detective Mike Logan, a role he had originated nearly two decades earlier.