Ramamurthy was born in Chicago to a Kannadiga Indian father and a Tamil Indian mother who had emigrated from India. He grew up speaking English and a little Kannada. His parents are Physicians. He has one sister who is also a physician. He and his sister were raised in San Antonio. There, he went to Keystone School and graduated in 1991. He is the cousin of Comedian and film Director Jay Chandrasekhar. Ramamurthy is married to Actress Olga Sosnovska with two children, daughter Halina (b. 2005) and son Alex (b. 2008), and lives in London.

In 2000, he appeared in NBC's television biblical miniseries In the Beginning in the role of Adam.

Ramamurthy joined the cast of the USA Network show Covert Affairs as Jai Wilcox from the second episode onward, replacing character Conrad Sheehan III, played by Eric Lively in the pilot. The show premiered in July 2010. In the season 3 premiere, his character was killed off.

On December 19, 2012, it was announced that he would appear in the CW show Beauty & the Beast as Gabriel Lowen, an assistant district attorney.

Ramamurthy attended Tufts University initially as a pre-med major to follow in his parents' footsteps. He was also a member of the Kappa Charge of Theta Delta Chi. He became interested in acting when he took an "Intro to Acting" class during his junior year as part of his graduation requirement. After participating in several plays — including Our Country's Good, he chose to change career goals. He graduated with a bachelor's degree in history and then attended the Webber Douglas Academy of Dramatic Art in London in 1996, graduating in 1998.

He appeared in his Heroes role in that series's continuation entitled Heroes Reborn, in 2015 and 2016.