A young goalkeeper at Tottenham who made the move to Sincil Bank, where he became a Lincoln City legend.

Impressing the Tottenham staff enough during a two-year youth training scheme to be offered a two year professional deal in 1997, his progress stopped short of the first team and at the end of the 1998-1999 season, the keeper was released to join Lincoln City.  Alan moved there initially on a trial basis, but in October 1999, he signed a two year contract, thanks to the Spurs Academy Director's (Colin Murphy) recommendation.  His first team debut came in February 2000 and he won the Young Player of the Year award that season, as he established himself in the first team.

The following season saw him continue between the posts and only a knee injury stopped him completing the season, keeping him out for three months.  However, he was awarded the "Away Player of the Season" and was awarded a new three-year deal.

At the start of 2001-02, Alan suffered a few dodgy games and was replaced for a while, but regained the gloves in September 2001 and kept goal for 140 consecutive league matches, until a knee injury kept him out of the match against Chester City on 24th September 2004.

With the appointment of Keith Alexander as Lincoln's manager, the concentration was on building a solid defence, with Marriott firmly part of the boss' plans.  18 clean sheets in 2002-03 saw the Imps reach the play-off final, but they lost to Bournemouth, but Marriott signed a new two year contract with the club.

In the next campaign, the finals were reached again, but Lincoln failed to make it through, although Marriott was once more awarded the "Away Player of the Season".  Another good season saw 19 clean sheets for Alan, but the side failed in the play-offs once more, with the only consolation for the keeper was another new deal, for three years, signed in June 2005.

Marriott was ever-present in the 2005-06 league season in which he reached 300 appearances for Lincoln and also broke a number of goalkeeping records.  He broke the Lincoln City appearance record for goalkeepers and also the number of clean sheets for the club.

It was in a game against Accrington Stanley on 25th August 2007 that Alan kept his 100th clean sheet, but a change in the manager's office saw Peter Jackson bring in his preferred goalie and despite forcing his way back into the team, he was released at the end of the season

On 9th July 2008, Alan moved on to Rushden and Diamonds on a two year deal, but left after five months to join Mansfield Town.