McArdle signed for Bradford City on 6 June 2012, signing a two-year contract. He made his debut on 11 August in a 1–0 win in the League Cup against Notts County. He made his league debut a week later against Gillingham. He made his home debut on 21 August, in a 1–0 win against Fleetwood Town. He scored his first goal for the club on 25 August in a 5–1 win against AFC Wimbledon. On 8 January, McArdle scored a header against Premier League side Aston Villa in the first leg of the semi-final of the League Cup, as Bradford incredibly won 3–1. He also played in the second leg, which saw Bradford advance to the final 4–3 on aggregate. He started in the final which Bradford lost to Premier League side Swansea City. He scored his second league goal for the club on 1 April, helping Bradford to a 3–1 away to Torquay United. He then scored in the 2013 Football League Two play-off Final, which Bradford won 3–0 against Northampton Town securing promotion to League One. On 3 August, the opening day of the season, McArdle scored a late header from a Raffaele De Vita corner to give Bradford a point in a 2–2 draw against Bristol City.