Suryanarayan Hegde, 78, was reported missing on Sunday.
He is an adjunct professor at the NYU Tandon School of Engineering, and police say he suffers from dementia.
He had last been seen at his apartment located on West 83rd Street on the Upper West Side around 10 p.m. Saturday.
He is said to be in good condition and has been reunited with family.
Further details have not been released.