In 2001, he was diagnosed with testicular cancer, but after surgery and an intensive treatment programme, he was given the all-clear a year later and resumed his playing career with The Lions.
Chopper found himself on loan at Cardiff City in 2004 before signing for Nottingham Forest later in the year. In total, the striker made 270 appearances for Millwall between 1998 and 2004, scoring a superb 98 goals.
He found his chances at the City Ground limited, so spent part of the 2005/6 season on loan at Gillingham, before moving back to The Den in January 2007. Almost two years later to that day, Chopper surpassed Teddy Sheringham's all-time goalscoring record in a 3-2 win at Crewe Alexandra, when he scored his 112th goal for the club.
In June 2011, after making a combined total of 432 appearances for Millwall and scoring 138 goals, Chopper moved to Southend United, where he remained for two injury-hit seasons before calling it a day on his playing career at the end of the 2012/13 season.
But, he was back at The Den once again just weeks later as a coach, working with both the first team and the Development Squad.
Months later, Chopper, alongside Academy Director Scott Fitzgerald, led the first team on a caretaker basis for a brief spell between December 2013 and January 2014 before Holloway's arrival, after which Neil returned to his duties as U21s manager. He held that position for a further 16 months before taking over from Holloway as interim manager until the end of the 2014/15 campaign - impressing enough during that spell to earn the job on a permanent basis days after the season came to its conclusion.
Chopper's first full season in charge saw the young manager, like his team, grow in confidence and stature as the campaign went on. Seeing young prospects such as Mahlon Romeo and Ben Thompson blend so effortlessly into a senior side that, in the manager's words, he wanted to 'play the Millwall way', was one of many positives to take from a year that saw The Lions pipped for promotion with a Play-Off Final defeat at Wembley at the hands of Barnsley.
However, 12 months later, Harris earned his redemption by steering the Millwall ship to another Wembley Final in the Play-Offs after a sixth-placed League finish and a two-legged Semi-Final win over Scunthorpe United; Steve Morison's late winner secured promotion to The Championship in a 1-0 victory over Bradford City.
The former Lions marksman guided the club to an impressive eighth-place finish in the Sky Bet Championship following promotion, a season which saw the team embark on a 17-match unbeaten run.
The manager's second season in The Championship was a difficult one, but Harris managed to steer The Lions to safety on the penultimate weekend of the campaign, following a draw at home to Stoke City.
Assistant Manager: David Livermore
David Livermore was appointed assistant manager to Neil Harris on a permanent basis in May 2015 after the pair impressed during a 10-game spell in interim charge of the first team at the tail end of the 2014/15 season.
David first came to The Den on loan from the youth ranks at Arsenal and signed a professional contract at Millwall in 1999 - going on to spend seven eventful years in South London, where his tough-tackling, no-nonsense performances would prove a hit with supporters.
He was a part of the team that secured the Division Two Championship in 2001 and played at the Millenium Stadium, Cardiff, in Millwall's first ever FA Cup Final in 2004.
In 2006, he crowned his Millwall career when he was awarded the Player of the Season trophy by the supporters.
David also holds the unusual distinction of being the player to score the last ever Football League goal in the 20th century when his injury-time winner secured three points for The Lions against Brentford in the 1999/2000 season.
David's playing days at Millwall came to an end in the summer of 2006 when he was snapped up by Leeds for £500,000. In a bizarre turn of events, he would move on to Hull City only two weeks later for the same figure.
His career would go on to include spells at Brighton & Hove Albion and Barnet, including loan periods at Luton Town and Oldham Athletic, and finally as a player/manager at Histon.
It was while at Histon in 2012 that Millwall came knocking again, with David being recruited to work alongside Justin Skinner with the club's U18 side.
And after over two years in the Academy set-up, former team-mate Harris opted to promote David to the role of interim assistant manager of the first team - a position he has held ever since.