Commander Katherine Pulaski, MD, was the chief medical officer aboard the USS Enterprise-D in 2365 while Dr. Beverly Crusher was serving as head of Starfleet Medical.
Prior to her posting to the Enterprise, Pulaski served as chief medical officer on the USS Repulse under the command of Captain Taggert. Like her predecessor eighty years before, Dr. Leonard McCoy, Dr. Pulaski had a transporter phobia. She rarely used the transporter while posted to that vessel, preferring to use shuttlecraft whenever possible. Taggert was fond of Pulaski, and said he would have given her a personal shuttlecraft if she had agreed to remain aboard the Repulse.
By 2365, when she transferred to the Enterprise, Pulaski carried the rank of commander, but unlike Dr. Crusher, she was not considered a bridge officer. Early in her career, Pulaski authored a groundbreaking research paper called "Linear Models of Viral Propagation". It was still the standard on the subject in 2365. She also performed two successful operations involving ocular implants, and offered the procedure to Lieutenant Geordi La Forge, although he turned down the opportunity.
Dr. Crusher decided to return to the Enterprise in 2366. Pulaski transferred off the ship sometime prior to Crusher's return.