The school, started in 1864, is located at Mazgaon. Mehta's visit was part of its 150th anniversary celebrations.
The school has planned a year-long celebration, including social initiatives by students, which began with today's function, where Mehta unveiled the 150 years celebration logo.
"Mehta, an alumnus of St Mary's ICSE, expresses great pride in being an ex-student of the institution and has a deep sense of nostalgia for the school. He last visited the institution in 1967," a release said.