[1][2][3] He started his career with Agona Swedru-based Division Two side, ABS FC, as an attacking midfielder but soon caught the attention of newly promoted Premier League side, Wassaman United, whose coach, Herbert Addo, converted Mumuni into a striker after discovering his potential during the 2012–2013 season.

After a successful Premiership debut, Ashanti Gold offered the young promising striker a 5-year contract at the start of the 2014-2015 league season with the view to develop him into a future asset for the club.

[16] His crowning moment actually came when he captained Black Stars B to win silver at the 2019 WAFU Cup of Nations in Senegal.

[17][18][19] As an icing on the cake, Mumuni was awarded the Golden Boot[20] after scoring four goals at the tournament, including a historic hat-trick against Ivory Coast in the semi-finals.

[21] That classic display compelled the then Black Stars coach, James Kwesi Appiah, to give Mumuni his maiden senior national team call-up against South Africa and São Tomé and Príncipe in the AFCON 2021 qualifiers in November 2019.