David McAllister's schoolboy career took in his local side, Rush Athletic, Home Farm and Bohemians. He then stepped up to U21 level with Drogheda United in 2007.

McAllister made one appearance for Drogheda's first team in a 2008 League Cup tie against Shelbourne, whom he then joined on loan two months later. In the remaining half of the 2008 season McAllister made 16 appearances for Shels, scoring seven goals.

In 2009 he signed permanently with Shelbourne, playing in the First Division under Dermot Keely. McAllister was an almost permanent fixture in Shels midfield as the club reached the promotion play-offs, and he finished the season as their top scorer with 16 league goals and two in the Cups.

For the 2010 season he was signed by Pete Mahon for Premier Division side St Patrick's Athletic, playing 40 league and Cup games, scoring 5 goals along the way. Widely regarded as one of the League of Ireland's most promising young midfielders he was attracting attention from England by the end of the season.

In November 2010 McAllister signed with English Championship side Sheffield United, managed by Welsh legend Gary Speed. He spent just over two years at Bramall Lane and scored three times in 29 league appearances, but he spent the latter stages of 2011/12 on loan at Shrewsbury Town. On 8 January 2013 he signed a permanent deal with the Shrews and he scored twice in 58 league appearances during his time there.

In October 2014 David went on a three month loan to Stevenage. He eventually signed permanently with them in January 2015 with whom he made 20 league appearances before being released in June 2016. He subsequently returned to Ireland and signed for Stephen Bradley at Shamrock Rovers on a one-year deal in December 2016. In November 2018, it was announced that David had left the Hoops.