Katherine Pulaski was the replacement Chief Medical Officer for Beverly Crusher during the second season of Star Trek: The Next Generation. She was played by Diana Muldaur, who had appeared on two episodes of Star Trek: The Original Series in the 1960s. Despite being a regular character on the show, Muldaur was always listed during the episode credits as a "Special Guest Star".

Prior to serving on the Enterprise, she served on the USS Repulse under Captain Taggart, who was very sorry to lose her.

Kate was a fairly traditional doctor, well versed in methods that her nurses considered archaic, such as splints. She also had an excellent bedside manner, and was known to prescribe "PCS" — Pulaski's Chicken Soup — for minor ailments. She shared many personality traits with Dr. Leonard McCoy of TOS, including a distrust of transporters and androids.

Pulaski was also well respected in the field of research. Her book, Linear Models of Viral Propagation, was the standard text on the subject for several years.

Her myriad interests included poker and Klingon literature.

Pulaski had been married and divorced three times by the time she was posted to the Enterprise in 2365. She remained on good terms with all three men. Prior to this she was involved with Kyle Riker, estranged father of Enterprise first officer William Riker, but they never married because of his preoccupation with his work.

She had some personality conflicts with Lieutenant Commander Data, insofar as someone can have personality conflicts with someone who's incapable of emotion. Despite the fact that Data has always been seen as alive (and later won the legal rights of a sentient being), Pulaski thought of Data as being a machine, and didn't understand why he wanted to be human. In another parallel with McCoy, this was similar to McCoy's ongoing debates with Mr. Spock over the nature of humanity.

Pulaski was never particularly popular with viewers, particularly fans of Gates McFadden. Following production of the second season, Muldaur left TNG in order to join the cast of L.A. Law, and McFadden was rehired to continue playing Dr. Crusher. In terms of official Star Trek canon, it has never been revealed why Pulaski left the Enterprise or what became of her afterward, although she has appeared in several officially licenced (but non-canon) novels.