The 27-year-old second-rower, who is equally as adept in the back-row, will make the switch to Scotstoun from United Rugby Championship rivals the Vodacom Bulls.
Standing at 6'6", Manjezi first came to prominence in South African schoolboy rugby, captaining St Andrew's College first XV en route to earning a place in the Eastern Province Academy.
He made his Currie Cup debut for the province at the age of just 20, making 15 appearances in the 2016/17 season prior to a move to the Griquas the following year.
An impressive stint in Griquas colours earned him a move to the Toyota Cheetahs ahead of the 2018/19 Guinness PRO14 campaign, where Manjezi immediately caught the eye of northern hemisphere observers.
His dynamism in the loose and set-piece expertise was a key factor in the Bloemfontein outfit earning a place in the playoffs for the first time in 2019, with only the COVID-19-enforced suspension of the league preventing Manjezi and the Cheetahs making it back-to-back playoff appearances in 2020.
Manjezi's form earned him a move to the Vodacom Bulls in the summer of 2020, helping the men from Pretoria to Currie Cup victory in 2020/21.
Away from rugby, the East London-born man studied at Nelson Mandela University in Port Elizabeth, as well as representing Eastern Province U19 at cricket prior to turning professional.
Speaking following signing with the Warriors, Manjezi told glasgowwarriors.org: "I'm looking forward to playing for Glasgow and taking on a new challenge.
"The opportunity of experiencing a new club outside of South Africa was one I couldn't turn down.
"I've played with Kyle Steyn previously and he speaks really highly of the club's culture, the hard work that the players put in and its ambitions.
"I think my skillset will compliment Glasgow's style of play - I like to play with ball in hand and carry hard.
"I can't wait to get up to Glasgow and put in the hard yards every single day and earn the right to wear the jersey."
Head Coach Danny Wilson added: "Sintu is the type of attacking presence we wanted to add to our depth in the pack.
"It's great to bolster our second-row options with another exciting player that brings a real carrying presence and good set piece skillset - Sintu also brings the added bonus of being able to play at six.
"We're looking forward to welcoming him to Scotstoun in the summer ahead of the new season."