Early career David Moberg Karlsson grew up just outside
Mariestad in Sweden where he made his first team debut for local
fifth tier club
IFK Mariestad as a fourteen-year-old. Due to his impressive performances with the Swedish youth national teams he was sought after by several clubs, but chose to sign a youth contract with
IFK Göteborg, the club he grew up supporting.
IFK Göteborg During the
2011 Allsvenskan season he started training with the first team and made his league debut in a game against
AIK. His progress led to IFK Göteborg signing him on a five-year first team contract in May 2012. At the start of the
2013 Allsvenskan season he finally scored his first league goal for the club in a 2–0 win against
IF Brommapojkarna.
Sunderland On 19 June 2013, he signed for
Premier League club
Sunderland for an estimated €1.9 million. Moberg Karlsson scored his first goal for Sunderland in the
Premier League Asia Trophy against
Tottenham Hotspur on 24 July 2013. He made his competitive debut against
Milton Keynes Dons in the
Football League Cup, starting in a 4–2 victory.
Loan to Kilmarnock On 31 January 2014, Karlsson joined
Kilmarnock on loan for the remainder of the season.
FC Nordsjælland On 13 August 2014, Karlsson joined Danish club
FC Nordsjælland on a four-year contract for an undisclosed fee.
IFK Norrköping On 21 June 2016, Karlsson joined
IFK Norrköping on a -year-long contract for an undisclosed fee.
Sparta Prague On 10 December 2018, Karlsson joined
AC Sparta Prague on a -year-long contract for an undisclosed fee.
Urawa Reds On 30 December 2021, Karlsson joined
Urawa Red Diamonds.
Aris On 19 July 2023,
Aris officially announced the acquisition of Karlsson on a season-long loan.
Return to IFK Norrköping On 27 July 2024, Karlsson rejoined
IFK Norrköping and was presented on field at half time during a game against
Kalmar FF, signing a contract through the 2026 season.
Tochigi City On 11 January 2026, Karlsson joined
J2 side
Tochigi City. == International career ==