Mordue was born in Edmondsley, County Durham, the fifth son of Thomas Mordue,. As a youth he played for various local village teams and was spotted by Barnsley whilst playing for Spennymoor United. He joined the Oakwell club in October 1906, and played 25 Second Division games with 12 goals. In April the following year he moved to London when he was sold to Woolwich Arsenal for £450, where he linked up with his brother-in-law, goalkeeperJimmy Ashcroft. Mordue made his debut for Arsenal on 13 April 1907 and went on to play 28 games for Arsenal in thirteen months, scoring one goal. Arsenal finished 7th and 14th in the league in the 1906–07 and 1907–08 seasons, and Mordue was considered one of the team's best assets. With Woolwich Arsenal in financial trouble, he was sold for £750 to Sunderland, returning to his native north-east in May 1908.
Sunderland
He made his Sunderland debut on 9 September 1908 at Middlesbrough scoring in a 3–0 victory. He soon became a fixture at outside right, contributing some vital goals including one against Newcastle United in a 9–1 victory at St James' Park on 5 December 1908. He went on to form an excellent partnership on the right-wing with Charlie Buchan and Francis Cuggy, his 15 goals helping the club to win the Football League Championship in 1913. Sunderland narrowly missed out on the Double, losing the FA Cup final 1–0 to Aston Villa, who themselves were runners-up in the League. Mordue also became Sunderland's main penalty taker, scoring 26 in total, reaching the age of 34 before he missed one in a competitive game. Mordue made two England appearances, making his debut against Ireland on 10 February 1912. In this match, he played alongside his Sunderland colleague George Holley as England ran out 6–1 victors. His second, and final, England match was also against Ireland a year later. In this match, Mordue was teamed up with his Sunderland colleagues Charlie Buchan and Francis Cuggy and although Buchan scored early in the game, England went down 2–1. Mordue also represented the Football League on three occasions. Mordue left Sunderland in 1920, having played 294 games in total, with 80 goals.
Later career
He was sold to Middlesbrough in May 1920, spending three years at Ayresome Park before accepting the position of player-manager at Durham City in February 1923, a post he held for twelve months. Mordue died on 6 March 1938.
