Mulenga started his career with the Zambian third-tier club Afrisport from his hometown of
Kitwe at a relatively late age – he only started playing organised football as an 18-year old. In the summer of 2004, he returned to France for a trial period at
Bastia alongside
Billy Mwanza. After the Corsican club did not offer him a contract,
LB Châteauroux showed interest in him and he was subsequently signed on a four-year contract. Mulenga thus became the second Zambian in the French professional divisions, after
Andrew Tembo who played for
Marseille in 1994. In his
Ligue 2 debut on 24 August 2004, Mulenga scored both goals in a 2–0 win over
Chamois Niortais. In the ensuing period, however, he suffered a large number of injuries, limiting his appearances in the league that year to 15. In the two seasons that followed, he played more often, but his goalscoring stagnated. In August 2007, he was sent on a one-season loan to
Ligue 1 club
RC Strasbourg. After this period the Zambian returned to Châteauroux. In late May 2009, the club announced that Mulenga had been signed by Dutch
Eredivisie club
FC Utrecht, who, after a disappointing season, had been looking for a striker and eventually signed him on a three-year contract. On 31 October 2010, in a match against
ADO Den Haag, he tore his right cruciate ligament and was sidelined for the entire 2010–11 season. On 14 August 2011, Mulenga made his comeback and marked this by turning a 0–2 deficit against
De Graafschap into a 2–2 final result after scoring two goals. In a match against
Ajax on 9 November, however, he tore his left cruciate ligament and was sidelined for eight months. In August 2014, Mulenga signed with Turkish club
Adana Demirspor, before moving to Chinese football six months later. He moved from
Shijiazhuang Ever Bright to
Liaoning Hongyun in January 2018, where he, in October 2018, became team captain. In February 2020, he signed a contract extension until the end of 2020. In April 2020, it was announced that Mulenga was suing his club, after not receiving his salary throughout the
2019 season. In May 2020, Liaoning Hongyun went bankrupt and Mulenga was left without a club. In October 2020, he joined Dutch second-tier
Eerste Divisie club
Go Ahead Eagles as a
free agent. He immediately scored in his debut on 17 October, after coming on as a substitute in the 69th minute against
FC Eindhoven, as Go Ahead won 3–0. On 30 April 2022, Mulenga announced his retirement from football after the
2021–22 season. He scored in his last match as a professional footballer, a 3–1 league loss to
SC Heerenveen, after having come on as a substitute. ==International career==