Nikhil was born and brought up in Hyderabad. His father is Shyam Siddhartha and mother is Veena Siddhartha. Nihil have one younger sister named Sonali and one younger brother named Rohit Siddhartha.

He completed his schooling in Hyderabad Public School, Begumpet and then transferred to St. Patricks' High School, Secunderabad. He was brilliant in school and was a merit student. He completed his graduation from Muffakham Jah College of Engineering and Technology, Hyderabad. 

Nikhil is very interested in films since his childhood. During his college days, he even took special course in dancing. His interest in direction got him a chance as Assistant director to Hyderabad Nawabs movie. He also did several little roles during his struggling period.

His first break came in the form of Happy Days. He played one of the four heroes in the movie and it won him instant fame and name. His first movie as solo lead is in Ankith, Pallavi and Friends which failed at the box office.

His first commercial hit as solo hero came in the form of Yuvatha directed by Parasuram. Later he acted in movies like Kalavar King, Om Shanthi and Alasyam Amrutham. In 2011, he teamed up with Chinni Krishna, a former associate of VV Vinayak for Veedu Theda. The movie went on to become a decent hit. Veedu Theda was followed by one more flop, Disco.

When his career almost seems to be on ventilator, Nikhil joined hands with Sudhir Varma, a debutant for Swamy Ra Ra. He underwent total makeover in his personality and styling. And the result is one of the biggest hit of the year in terms of return of investment. He followed the success with one more in 2014 in the form of Karthikeya directed by one more new comer, Chandoo Mondeti. Incidentally Colours Swathi is the female lead in both the films proving to be his lucky charm.

• Nikhil is a big fan of Ravi Teja. There is always an impact of the actor in Nikhil’s acting. Some people even call him Junior Ravi Teja due to his energy in acting.
• Nikhil is so fond of his parents that he tattooed the names of his father and mother on both his hands.