Davidson signed for Salford's Academy from amateur club Blackbrook Royals, after previously playing for Wigan St Patrick's and Westhoughton Lions.
He made his first team début for Salford in a Round 6 win over Hull Kingston Rovers in 2011's Super League XVI, on 18 March 2011, coming on for Ryan Boyle at prop in the first half.
The demands of the, then, Head Coach and the interpretation of the contract rules led to that strong team succumbing to two successive losses and not gaining entry to the Grand Final.
During the latter stages of the 2013 season, circumstances forced some younger players forward and among them, Alex appeared as substitute in the Super League matches against Huddersfield Giants (away) and Leeds Rhinos (home).
In July 2021, Alex signed for London Skolars and played his debut match for them at home to Doncaster where a 16 all draw was recorded.