St. Sebastian's basketball has a winning tradition dating back to the School's founding in 1941. Mr. Frank Power led the Arrows to their first Class C Championship in 1952. He added a second Class C Title the next year. Following his predecessor's example, Father Daniel Gilmartin coached the Arrows to back-to-back Class B Championships in 1964 and 1965. Coach Guden helmed the Arrows from 1972-75, leading his team to the New England Prep School Tournament in both 1973 and 1974. Coach John Borden took the reins in 1975 and led the team to three Class C Championships, and one in each of the next three decades (1977, 1983, 1996). Coach Borden retired in 2004, following thirty-plus years of teaching and coaching, and over 400 victories.
The St. Sebastian's philosophy is one of inclusion, where learning, competing, and participation are paramount. There are no cuts at sub-varsity level, and the basketball program consists of five teams; 7th, 8th, 9th, JV, and Varsity. All are coached by full-time faculty members. The Varsity team participates in the highly competitive Independent School League (ISL), which consists of sixteen teams, and is also a member of NEPSAC's Class A division. In addition to the ISL schedule, the Arrows help host the Seacoast Classic Class A Holiday tournament, which takes place the week leading into Christmas vacation. Many of our student athletes have gone on to compete at the next level. In recent years, Arrows have played for Amherst, Williams, Bentley, and Stonehill.