He was appointed the commander of the Namibian Army in 2011, and NDF Chief on 31 December 2013, a position from which he retired on 31 March 2020.

Mutwa's military career began in 1975 when he joined the Peoples Liberational Army of Namibia in Zambia.

In 1990 he joined the Namibian Defence Force as a pioneer and was given the rank of lieutenant Colonel and appointed assistant director: military intelligence.

In 1994 he was reassigned as the commanding officer of Namibia's logistic support battalion in Grootfontein with the same rank.

In 1998 he was redeployed as the army chief of staff: personnel and logistics, in this position he was then deployed to Operation Atlantic, Namibia's contribution to the SADC allied forces to the DRC during the Second Congo War.

In 2006 he was promoted to brigadier general and appointed the chief of staff logistics at Defence HQ.