Youth Mumin was born in
Accra and was a part of the academy at
Right to Dream. The defender was an integral part of the RtD U18 team, helping them win back-to-back Gothia Cup tournaments in 2014 and in 2015.
FC Nordsjælland On 2 August 2016, it was confirmed, that Mumin had signed a professional contract with
Danish Superliga side
FC Nordsjælland, and joined their U19 squad. Mumin made his Nordsjælland debut on 7 August 2016, just a few days after signing with the club. Mumin started on the bench, but replaced
Viktor Tranberg in the 62nd minute in a 2–1 defeat against
AaB in the Danish Superliga. He was promoted to the first team squad for the 2017–18 season. After Nordsjælland sold
Andreas Skovgaard in January 2019, Mumin began to play continuously.
Loan to HB Køge On 23 January 2018, Mumin was loaned out to
Danish 1st Division club
HB Køge for the rest of the season.
Vitória de Guimarães On 15 August 2020, Portuguese
Primeira Liga club
Vitória S.C. signed Mumin on a four-year deal. Mumin got shirt number 6 and made his official debut for the club in the Primeira Liga on 18 September 2020 against
Belenenses SAD, playing all 90 minutes.
Rayo Vallecano On 1 September 2022, Mumin signed a four-year contract with
La Liga side
Rayo Vallecano. Mumin got his debut for the Spanish side on 17 September 2022 against
Athletic Bilbao. On 1 March 2025, Mumin sustained a
cruciate ligament injury in a match against
Sevilla, which was expected to keep him sidelined for an extended period. ==International career==