Magno and Hanoi agreed on terms Friday, with the Brazilian passing his medical test on Saturday. He is the capital club's first recruit ahead of the 2021 season.
The attacking midfielder boasts great dribbling and finishing skills, helping him score eight goals in the 2020 season and Saigon finish third on the V. League 1 table.
Though Saigon sought to retain Magno, the 26-year-old decided to sign with Hanoi, which had offered him a monthly salary of more than $20,000, twice his prior wage.
Previously, Hanoi has chosen not to extend the contracts of Senegalese striker Pape Omar Faye, 33, who struggled to adapt to the intense schedule, and French forward Pape Ibou Kebé, who failed to prove himself at the club. Magno is expected to be their perfect replacement.
Hanoi enjoyed moderate success during the 2020 season, winning National Cup and finishing second in V. League 1.
With the addition of Magno, Hanoi currently fields three foreign players, the other two being Ugandan midfielder Moses Oloya and Jamaican forward Rimario Gordon.
The capital club also extended the contracts with keeper Bui Tan Truong and midfielder Le Tan Tai, besides recalling some of its players on loan to other clubs.
2020 V. League 1 wrapped up on November 8 with Viettel FC as champions, followed by Hanoi and Saigon. The 2021 V. League 1 season is scheduled to start on January 16.