Former Arsenal defender Scott Marshall joined Norwich City in the summer of 2012 as their Under 21s Development Squad Lead Coach

Marshall is the son of former Hearts and England under-23 goalkeeper Gordon Marshall and the brother of Gordon Jnr. who played in goal for Celtic and Scotland. He started his playing career at Arsenal and broke into their first team at the age of 19, winning five Scotland under-21 caps. He scored his only goal for the Gunners in their 2–0 victory over Newcastle United in March 1996 and at the end of that season was voted as the Gunners' Young Player of the Year by the supporters. In seven seasons with Arsenal he only made 25 appearances, spending spells on loan at Rotherham United and Sheffield United.

In August 1998, Dave Jones signed him for Southampton on a free transfer. Saints thought they had made a transfer coup, but Marshall soon showed why Arsenal let him go, scoring an own goal in his debut against Leeds United in a 3–0 defeat on 8th September 1998, repeating this four days later in a 4–0 defeat at Newcastle United

He never appeared again for Saints and went out on loan to Celtic where his only appearance was in the 'Old Firm' derby with Rangers in May 1999 when he ended up on the wrong end of 3–0 scoreline

Marshall then joined Brentford in October 1999 for a fee of £250,000. Unfortunately, after scoring yet another own goal in his third appearance for the Bees, he then suffered back problems which caused him to miss most of the 2001–02 season. After battling his way back to fitness, he at last gained regular first team football making a total of 94 appearances for the Bees, scoring seven goals.

In November 2003, he became Tony Adams' first signing as Wycombe Wanderers manager when he was brought on to shore up their defence. He made eight league appearances. At the end of the 2003–04 season, he was re-signed on a non-contract basis, but on 27th August 2004 he announced his retirement from the professional game.

After retiring, he took up a youth coach role at Brentford in 2007. He then spent time living and working in Muscat, Sultanate of Oman, running the Arsenal Soccer School

Marshall joined Paul Lambert's Aston Villa as first team coach on 25th June 2013. Lambert said "It takes time to build a team and you also need time to build the staff around you," said Lambert, who has so far also made five summer signings. Scott worked with me at Wycombe. He has a very professional approach and will definitely be a big hand for myself."

He was given more responsibility when assistant manager Roy Keane left Villa in the autumn of 2015.

Marshall was appointed to caretaker manager on 11th February 2015, along with goalkeeping coach and namesake Andy Marshall, following Villa's sacking of Paul Lambert. They took charge of one Villa game, a 2-1 FA Cup victory over Leicester on 15th February 2015. By then former Norwich, Blackburn and Tottenham midfielder Tim Sherwood had been appointed as Villa manager on a three year contract. Marshall left Villa on 17th February and was replaced by former Norwich first-team coach Mark Robson

On 1st September 2017, Marshall joined Reading as their Under-23s manager. He had two games as Reading's caretaker manager in December 2018.

On 22nd July 2021 he was appointed as Assistant Manager at Swindon Town. Marshall later followed Swindon manager Ben Garner to Charlton Athletic and Colchester. In October 2023 when Garner was sacked by Colchester, Marshall was made caretaker manager after a contract issue meant interim head coach Matthew Etherington had to step down. Etherington was appointed before the Grimsby game but was not able to sit on the bench at Accrington after former club Crawley told them he is still under contract with them until May 2024. As a result Marshall was placed in charge. He said "To go away to Grimsby, go away to Accrington and come away with six points is fantastic. I thought the boys dug in and showed huge amounts of character. Once we got the goal ahead you could see a real determination in the group to hang on to it. When you see that in a squad, that's one of the fundamentals of football, isn't it? Where there's a bit of spirit and character, hanging on to something and showing a bit of grit and determination - people want to see that."