Cadden made his Motherwell debut as a substitute in a 4–1 win against Hearts on 1 March 2014. On 6 March 2015, Cadden joined Scottish League Two club Albion Roverson loan until the end of the season. Cadden scored his first career goal on 4 April 2015, as Albion Rovers beat Berwick Rangers 2–0, and another in Albion Rovers' league-winning match against Clyde. His loan spell concluded with the club being promoted as divisional winners. On 30 January 2016, Cadden scored his first goal for Motherwell in a 2–2 draw away to Dundee. In March 2016, he signed a new contract with the club to run until the summer of 2018. By now establishing himself in the first team, he also contributed to Motherwell's Under-20s winning the Scottish Youth Cupfor the first time. Cadden signed another contract with Motherwell in November 2016, extending its term by another year. He played in the finals of the 2017–18 League Cup and the 2017–18 Scottish Cup, both of which resulted in 2–0 defeats for Motherwell at the hands of Celtic.
Columbus Crew SC
On 23 July 2019, free agent Cadden signed for Major League Soccer side Columbus Crew SC; it was announced that he would be immediately loaned to English club Oxford United and would join the Crew in advance of the 2020 season. Motherwell stated they would negotiate for a training compensation fee, due to no formal arrangement being in place with MLS in respect of clubs which had developed a young player receiving a payment when they left out of contract. Cadden started the 2020 season as depth at both the wing and wing-back positions, but was widely considered the successor to 33-year-old GhanaianHarrison Afful. Cadden made his debut for the Crew against New York City FC in the first game of the season. He came on in the 87th minute for fellow debutante Lucas Zelarayán.
Oxford United
Cadden made his Oxford debut in a 1–1 draw at Sunderland on the opening day of the 2019–20 season. During Cadden's loan spell, he made 21 appearances for Oxford and was widely considered one of the best left backs in EFL League One. Oxford manager Karl Robinson looked to make the loan permanent, but had its advances rejected by the Crew. This brewed controversy between the fans of the two teams debating whether Oxford United or Columbus was the better destination for the Scottish International.
International
In August 2016, Cadden was named in the Scotland under-21 squad for the first time ahead of the European Under-21 Championship qualifiers against Macedonia and Ukraine, receiving the call having initially been left out the squad. He made his debut against Ukraine on 6 September 2016. On 17 May 2018, Cadden was called up to the Scotland squad for the first time ahead of their friendlies against Peru and Mexico; he made his full Scotland debut on 29 May, in a 2–0 defeat to Peru.
