Robert Bruce Muir was born on April 7, 1898, in Boston, Massachusetts. Although swimming was to become his life, he was a late learner. At Brookline High School and Swimming Club, Muir learned how to swim under the tutelage of later Olympic swimming coach, Matt Mann. At age 19, only seven years later, Muir was to win the national YMCA breaststroke championship. Muir met fellow swimmer Ione Louise Casavant during his competitive years, and the two were married in 1918. After a brief tour of duty in the U.S. Navy, Muir began his coaching career with the Boston University and MIT swim teams in 1921. During the 1920s and early 1930s, Muir also coached the Boston Swimming Association, taught swimming at Harvard University and the Silver Bay Training School, and coached the Harvard freshmen and varsity diving teams.
In 1936, after more than two decades of extensive involvement in the Boston competitive swimming scene, Muir accepted the position of Head Coach of the Williams College swim team. His mature coaching talent transformed Williams into a swimming powerhouse. During Muir's tenure, Williams experienced 185 wins, 44 losses, and four ties. Twenty-seven of his teams were undefeated, and nine of his teams experienced only one loss. Throughout his Williams coaching career, Muir earned the respect of his teams and the affection of his swimmers. He developed a number of close mentoring relationships with several students including Michael Dively (Class of 1961) and Felix "Buster" Grossman (Class of 1956).
Muir and his wife Ione spent summers at the Lawrence Beach Club at Atlantic Beach Long Island, where he was Athletic Director and Swimming Coach and where both he and Ione taught thousands of children to swim over the years.
Muir and Ione also participated in several Olympic swimming delegations beginning in 1936. Ione herself served as a chaperone for the women's team and sometimes an assistant coach. In what was to be one of the defining events of his life, Muir was appointed head coach of the U.S. swim team for the 1956 Olympics in Melbourne, Australia.
In addition to his personal swimming career and coaching, Muir also contributed many technical improvements to the sport, for example the blueprint for a more efficient kick board design, and the practice of assigning swimmers to pool lanes according to their times to correct for the water's drag.
Muir was rewarded for both his consistent success with Williams teams and his national reputation for excellence. Williams College bestowed on Muir an honorary M.A. degree in 1957 in honor of his coaching success. In 1961, on the occasion of his 25th anniversary at Williams, Muir was honored by a "Bob Muir Day" celebration, receiving several hundred letters of congratulations from colleagues and friends. He was awarded the National Collegiate and Scholastic Swimming Trophy by the College Swimming Coaches Association of America in 1966, and in 1989 Muir was inducted into the International Swimming Hall of Fame as an outstanding coach.
Muir served as Williams' Head Coach until his retirement in 1966, when the new swimming pool was christened the Bob Muir Pool. He maintained an active presence on the team well into his nineties. After a rewarding life and a brilliant career, Bob Muir died in 1997 at the age of 99.