The 26-year-old heads to the Estádio do Morumbi with São Paulo currently sitting sixth in the Campeonato Brasileiro Série A and in pursuit of qualification for the Copa Libertadores.
Jamal joined Newcastle United from Norwich City in 2020 and has made 36 competitive appearances for the Magpies.
His last outing for the club was in a 1-0 pre-season victory over Stade Brestois in August.
The Luton-born left-back spent the duration of last season on loan at Watford, playing 38 times for the Hornets in all competitions.
At international level, Jamal has 36 senior caps for Northern Ireland.
The move remains subject to international clearance.