Years & Years' music has been described as electropop, mixing R&B and 1990s house elements.
The band's debut studio album, Communion, debuted at number one on the UK Albums Chart in July 2015 and was the fastest-selling debut album of the year from a UK signed band. Their biggest hit single "King" from their debut album Communion reached number one in the UK Singles Chart in March 2015, and peaked within the top ten of the charts in many countries. In 2019, the band performed at the Glastonbury Festival where Alexander gave a speech that was universally praised by fans and media.