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 New England Championship in 1952 and added a second title the following year. Following his predecessor's example, Father Daniel Gilmartin coached the Arrows to back-to-back Championships in 1964 and 1965. Coach John Borden took the reins in 1975 and led the team to three New England Championships and the school’s first three Independent School League (ISL) titles. Coach Borden retired in 2004, following thirty-plus years of teaching and coaching, and over 400 victories. In 2022 the Arrows once again secured an ISL title and set the school record for wins in a season finishing the year with a 24-3 record.
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 Class A Holiday tournament, and play in the Zero Gravity Prep Classic, Scholar Roundball, and Hoop Hall tournaments. Many of our student athletes have gone on to compete at the Division I, II, and III levels.