The fourth season of NYPD Blue saw the introduction of two important new cast members: Andrea Thompson as Detective Jill Kirkendall, fearless crime-fighter, single mother, and potential threat to the burgeoning romance between Det. Bobby Simone (Jimmy Smits) and Det. Diane Russell (Kim Delaney); and Lourdes Benedicto as Gina Colon, one of several novice 15th precinct administrative assistants, and the new love interest for Det. James Martinez (Nicholas Turturro). While Andrea Thompson would ultimately be promoted to series regular, Lourdes Benedicto remained among the recurring-character ranks, albeit a prominent one. In other developments, Det. Greg Medavoy (Gordon Clapp) went on a crash diet and somewhat reluctantly volunteered to be the father of gay cop Abby Sullivans (Paige Turco) baby; Bobby Simone inherited a shabby Brooklyn apartment building, involving him in a whole new crop of oddball characters, chief among them surly building super Henry Coffield (Willie Garson); combustible Det. Andy Sipowicz (Dennis Franz) continued to behave in an unpredictable fashion from one day to the next, though he was considerably humanized by his newborn son Theo (the mother, of course, was Assistant DA Sylvia Costas [Sharon Lawrence]); and recovering alcoholic Diane Russell, beset by professional and personal woes, suffered a nervous breakdown.

Of the major story arcs, two involved delicate and potentially deadly undercover operations. Diane Russell was assigned to get close to handsome, hair-triggered mob functionary Jimmy Liery (Christopher Meloni); it was the grim outcome of this case that nearly pushed Diane over the edge and back into a bottle. And, prodded by the Feds, who were anxious to build a case against hoodlum Joey Salvo (Peter Onorati), Bobby Simone infiltrated Salvos circle of friends and performed a few conspicuous favors for Joey. The fact that Bobbys covert activities aroused the suspicions of Internal Affairs very nearly lost Simone his badge -- and also set the stage for season fours cliffhanger finale. As was the case in the three previous years, NYPD Blue collected quite a few statuettes at the annual Emmy awards presentation. Dennis Franz copped his third Emmy as Outstanding Lead Actor; Kim Delaney was honored as Outstanding Supporting Actress; and David Milch, Stephen Gaghan, and Michael R. Perry shared an award for their scripting of the episode Wheres Swaldo? ~ Hal Erickson, All Movie Guide