Born in Bicester, Sam was captain of United’s successful under-18 side, having initially joined the U’s at the age of nine. He was awarded a professional contract upon completion of his scholarship at the end of the 2012/13 season. He signed a new contract in May 2014 and another in June 2015.

Sam scored his first goal for the club against Southend on 17th January 2015. Although initially a centre back, Sam played regularly at right back during the 2018/19 season. He signed another one-year contract in March 2017 and another in June 2018 before being offered a two-year deal extension in June 2020. In March 2021 he extended this by a further three years. He is United’s current longest-serving player and was voted both Players’ and Supporters’ Player of the Year for 2020/21.

Since the conclusion of the 2020/21 season, Sam has made an additional 144 appearances for the Club (as of August 2025), consistently demonstrating his professionalism. One of his standout moments came in April, when his crucial late winning goal secured victory away at Sheffield Wednesday.