 <unk> by American actress Diana Muldaur , Pulaski replaced the character of Commander Beverly Crusher for the second season after Gates McFadden 's contract was not renewed . Pulaski first appeared in the second season opener " The Child " , and made her final appearance in " Shades of Gray " . Before playing the role of Pulaski on The Next Generation , Muldaur appeared in Star Trek : The Original Series , playing different characters in the episodes " Return to Tomorrow " and " Is There in Truth No Beauty ? " She later worked with series creator Gene Roddenberry on a pilot for the series Planet Earth . McFadden returned to replace Muldaur in the third season , reprising her role as Dr. Crusher for the remainder of the series . 
