Gunn joined Southampton in July 2018, signing a five-year deal with the club, for a fee estimated at £13.5 million. He made his debut for the club on 28 August 2018 in an EFL Cup tie against Brighton & Hove Albion, and his Premier League debut on 2 January 2019, making several vital saves and keeping a clean sheet and earning the man of the match award in a 0–0 draw against Chelsea.

After spending the 2017–18 season on loan at boyhood club Norwich, enjoying a good run of performances throughout the entire Championship campaign, Gunn signed for Southampton in the summer of 2018, for a transfer fee of £13.5 million.

For the 2017–18 season, Gunn was loaned back to Norwich of the EFL Championship. He made his first-team debut in Norwich’s first match of the season, away to Fulham. He got his first professional football clean sheet on 16 August 2017, in a 2–0 home win over Queens Park Rangers at Carrow Road. He would ultimately be the only player to be ever present for Norwich in the league during the season, also being ever present in the FA Cup and making three appearances in the EFL Cup. At the end of the season, Norwich fans voted him third in the Player of the Season vote behind James Maddison and Grant Hanley.

Gunn received his first call up to the England national team in November 2017 for a friendly match against Brazil, after Jack Butland withdrew from the squad with an injury. In March 2018, Gunn was offered the opportunity by Scotland manager Alex McLeish to switch allegiances to Scotland, but decided to stay with the England national team, and was called up by Gareth Southgate to their training camp ahead of the 2018 FIFA World Cup.

Gunn began his career at his hometown club Norwich City, before moving to Manchester City in 2011, for which a tribunal decided Manchester City had to pay £250,000. He signed a three-year professional contract in June 2013. He was named on the substitutes bench on a number of occasions throughout the 2016–17 season, but did not play for Manchester City that season.

Angus Fraser James Gunn (born 22 January 1996) is an English professional footballer who plays as a goalkeeper for Premier League club Southampton. He has represented England at under-21 level. He began his career at his hometown club Norwich City, before joining Manchester City in 2011, eventually signing his first professional contract in 2013.