In February 2003, 15 year old central defender Adam Gusterson made the record books when he became the second youngest player to play for Norwich's Reserve team. The youngest player to achieve this is Gusterson's Under-15 colleague Rossi Jarvis. A regular in the Under-15s, Adam was called up for the reserve team clash with Brentford on 5th February 2003 as Norwich's youth team were playing the same day against West Ham in the FA Youth Cup. Many of the regulars in the reserves were playing for the youth team.

Although much of the 2003/4 season was hampered by a serious knee injury that had to be reconstructed, Adam joined the Norwich City Academy as a full-time scholar in July 2004. Academy Director Ricky Martin said "Adam's one we use as an example to the young schoolboys in terms of what's required of them passing-wise, short and long, off both left and right foot -something that he's only achieved through a lot of hard work."

Unfortunately Adam was not offered a professional contract by the Canaries in April 2006 and spent the remainder of the 2005/6 season with Kings Lynn. He then joined the Linnets for pre-season training but was not guaranteed first team football so he left to join Robert Taylor's Dereham Town on 27th July 2006

In february 2008, Adam was named as Dereham's manager until the end of the 2007/8 season following Robert Taylor's sacking. His reign as caretaker manager at Dereham Town got off to a good start as the Magpies swept aside Ridgeons Premier bottom club Newmarket Town 2-0 at Aldiss Park in front of a 137 crowd. Gusterson also worked for Norwich City as a Football In The Community coach but currently works for Norfolk County FA at their football development centre and for Personal Best Soccer.

Adam helped Dereham win the Thurlow Nunn Eastern Counties Leauge title in 2012/13, winning a place in the Ryman League for 2013/14. He made 36 appearances that season

In 2015, Gusterson and Olly Willis became joint-managers of Harleston Town. He also manages the Norfolk Under-18 Representative Squad along with Willis. They led Harleston to promotion into the Eastern Counties League and finished top of the Eastern Counties First Division in 2017/18. On 8th January 2019, Willis and Gusterson were named the new managers of Dereham Town following the sacking of Neal Simmons. A club statement from Harleston said: “The club are sad to announce the imminent departures of our first team management staff, Adam Gusterson, Olly Willis & Chris Linehan. The trio have been offered an incredible opportunity at a higher level and they leave the club with our blessing and best wishes. We will forever be grateful for their incredible achievements at the club, cumulating in the Sterry & Mummerry cup double last season. They leave the team in a fantastic position at the top of the Thurlow Nunn 1st division and will always be welcome back at the club. A further statement will be released in due course regarding the vacant management position.”

He moved to Lowestoft in the summer of 2022 as assistant to Jamie Godbold. In 2023/24 they won the Isthmian League North title.

On 17th August 2024 he stepped down from his role at Lowestoft due to increased work commitments. Blues boss Jamie Godbold said: "Gussy has been an influential figure in our club over the past two years and an absolute joy to work with. He will be severely missed in our dressing room."