The 19-year-old, who grew up locally before coming through AFC Wimbledon's academy and later joining City in 2023, will wear the number one shirt during his spell at Gander Green Lane.
Brits made 19 appearances for City's development squad last season and produced a memorable moment in Europe, saving a penalty to help secure a clean sheet in a 4-0 UEFA Youth League win over Real Madrid.
The goalkeeper says the chance to play close to home for a club he has long admired made the decision an easy one.
"I'm buzzing to be here and join the club for the season," Brits told the Sutton United website.
"Being a local lad who grew up in the area and seeing first-hand the impact the club makes on the local community makes the move even more special.
"As soon as I spoke to the gaffer and heard about the plans and ambitions for the season ahead, it was a complete no-brainer for me."
Brits becomes the latest young goalkeeper to leave Manchester City's academy in search of regular first-team football, following a well-trodden pathway for the club's highly regarded development squad graduates. His performances at development level, including that penalty save against Real Madrid's youth side, have marked him out as one of the more promising young shot-stoppers in City's system.
For Sutton, the loan represents a chance to add fresh competition between the posts as they prepare for the new season, with the club's local ties to Brits adding an extra layer of significance to the deal beyond simply strengthening the squad on paper.
Sutton, who compete in the National League, have increasingly looked to parent clubs' academies for loan talent in recent years, and Brits' arrival continues that trend. He is regarded within City's academy set-up as a strong shot-stopper with good command of his area, attributes that should serve him well as he adjusts to senior non-league football for the first time in his career.
Given his local roots, the move also carries extra meaning for a goalkeeper who grew up watching Sutton before beginning his own journey through the academy system, and he will now be hoping a productive season on loan can accelerate his path towards regular first-team opportunities in the years ahead.