[1] Thummalapally is the son of T. Dharma Reddy, a retired scientist who worked for Andhra Pradesh Forensic Sciences Laboratory, and T. Padmaja.

He came to America in 1974, and attended Occidental College in Los Angeles, where he spent a summer as Barack Obama's roommate.

[2][3] Prior to his appointment as Ambassador Thummalapally was CEO of MAM-A Inc (formerly known as Mitsui Advanced Media).

He has two patents in optical disc manufacturing design.

degree from California State University and took graduate classes in business administration from both CSU and the University of Tennessee.