An official exchange of roles with his predecessor, Win Daki, took place at the PNG Defence Force Headquarters at Murray Barracks, in Port Moresby.
Relative department heads attended the handover-takeover ceremony, to welcome the new Minister for Defence.
They include the National Volunteer Service, National Disaster Office, National Defence Council and the PNG Fire Service.
The new minister was welcomed with an official gun salute by military personnel.
Minister Joseph thanked the government of the day for entrusting him with the ministry.