He was selected to the Dean's List during his final two semesters for his academic excellence. Realising after 2 years that it wasn't in his best interest, he transferred to Columbia College Chicago, from where he graduated with a B.A in Film Studies in 1997. For his undergraduate studies, he enrolled in an engineering course in Michigan. Sumanth studied at the Hyderabad Public School, graduating in 1991. They, however, were divorced amicably in 2006. In August 2004, Sumanth married former actress Keerthi Reddy. Actors Rana Daggubati, Naga Chaitanya, Akhil Akkineni, and Sushanth are also his cousins. Also, noted film producer Daggubati Suresh Babu and actor Venkatesh Daggubati are his cousins. Ramanaidu is his uncle from his paternal side. Prominent actor Nagarjuna Akkineni is his maternal uncle. Sumanth has one sister, Supriya Yarlagadda, who is the executive director of Annapurna Studios. Sumanth's father Surendra Yarlagadda is a retired film producer, noted for several hit films such as Shiva, Rao Gari Illu, Gaayam, Muchattaga Mugguru and Collector Gari Abbayi.
Subsequently, Sumanth was adopted by his maternal grandparents. The latter had often said that his busy acting career prevented him from fully experiencing fatherhood with his own children, so he wished to raise his first grandchild himself. Sumanth, however, remained in India on the request of his grandfather Akkineni Nageswara Rao, who was then on a hiatus from films after a major heart surgery. A few months after his birth, Sumanth's parents returned to the US where they were residing. Satyavathi Akkineni and the eldest grand child of the Telugu film actor Akkineni Nageswara Rao.
He is the only son of Surendra Yarlagadda and
Sumanth was born in Hyderabad, India, on 9 February 1975.