This comes after the Soweto giants announced that they agreed terms with the Clever Boys over the services of the Malawi international last week.
Pirates have now disclosed that Mhango has officially joined the club after signing a three-year deal.
"The 26-year old has penned a three year deal with the Buccaneers," a club statement read on Thursday.
“I am happy to have joined this wonderful club and I look forward to the season ahead," Mhango said.
Mhango has joined the rest of his new teammates on camp in Rustenburg, North West.
The Chiweta-born player has officially become Pirates' eighth signing ahead of the new 2019/20 campaign which set to start next month.
Pirates have already confirmed the signing of Kabelo Dlamini, Siphesihle Ndlovu, Tshegofatso Mabaso, Fortune Makaringe, Bongani Sam, Joris Delle as well as Tebogo Tlolane.
Bucs head coach Milutin 'Micho' Sredojevic will be expected to guide the team to its maiden major trophy since 2014 after the club reinforced the squad.