Amrinder captained the Indian squad at the AFC Under-23 championship qualifiers in Bangladesh this year.
He also played an important role with Atletico de Kolkata in the last season of the cash-rich league and contributed to Bengaluru FC, which clinched the 2015-16 title, thus becoming a permanent fixture in the senior national team squad.
Commenting on the selection, Indranil Das Blah, CEO of Mumbai City FC, said: "Amrinder is one of the finest goalkeepers in the country. He brings a wealth of experience at a young age and a hunger that that is extremely good for a team.
"All of us are really excited to welcome him to the Mumbai City FC family."