Born in Brooklyn, New York, of Ukrainian ancestry, Stanley Drucker began clarinet studies at age ten with Leon Russianoff, and remained his student for five years. He attended the High School of Music & Art (now the Fiorello H. LaGuardia High School of Music & Art and Performing Arts, at Lincoln Square). Drucker entered the Curtis Institute of Music at age 15, but left Curtis after one year, recruited to the Indianapolis Symphony Orchestra. After a year, he worked with the Busch Little Symphony, organized by Adolf Busch. He then became principal clarinetist of the Buffalo Philharmonic Orchestra.
In 1948, Drucker won a post in the New York Philharmonic clarinet section. In 1960, he became the orchestra's principal clarinetist, where he remained for the duration of his career. His time with the New York Philharmonic has included nearly 150 solo appearances with the orchestra. He gave the first performances of clarinet concerti by John Corigliano and William Bolcom, both of these commissions for the New York Philharmonic. Drucker has appeared on two recordings of the Corigliano Clarinet Concerto, a studio recording conducted by Zubin Mehta and a live recording of the 1977 premiere performance conducted by Leonard Bernstein.
In January 2008, the New York Philharmonic announced Drucker's retirement from the orchestra at the close of the 2008-2009 season, for a total of 61 years with the orchestra and 49 years as its principal clarinet. His final solo appearance with the orchestra was in June 2009, in performances of the clarinet concerto of Aaron Copland. Drucker is highly regarded for his musicianship and his longevity of service with the New York Philharmonic, totaling 10,200 concerts, such as expressed by Gustavo Dudamel in November 2007: "He's a legend. The history of the orchestra is in him."
On Thursday, June 4, 2009, Drucker was awarded a Guinness World Record for longest career as a clarinetist after his performance of Aaron Copland's Clarinet Concerto with the orchestra. Guinness thus logged his Philharmonic career at "62 years, 7 months and 1 day as of June 4, 2009". In 2010, Stanley Drucker received an honorary doctorate in music from the University of Florida.
Drucker is married to Naomi Drucker, former principal clarinetist of the North Carolina Symphony and current adjunct assistant professor of music at Hofstra University. They have two children, Leon, who is the double bassist for The Stray Cats under the stage name of "Lee Rocker", and Rosanne, an alternative-country singer-songwriter. Drucker has the distinction of being one of the few living orchestral musicians whose biography appears in the New Grove Dictionary of Music and Musicians.