The appointment comes after Balderton made investments in Bebo, Betfair and Setanta. Mistry will take on a role that will feature him seeking out new investment opportunies across the media industry.
Mistry was part of the management team that successfully sold Emap's consumer magazine business, including titles such as Zoo and FHM, to H Bauer for £1.1bn. He left the company is March.
During his eight years at Emap, Mistry was responsible for digital development and oversaw the launch of Box TV, the music TV joint venture with Channel 4, and Zoo magazine.
Prior to Emap, Mistry worked at The Boston Consulting Group, where he advised clients across a range of industries in Europe, China, Japan and US.
He started his career as a brand manager at Procter & Gamble, running FMCG brands in the UK and across Western Europe.
Barry Maloney, a partner at Balderton Capital, said: "Dharmash has a broad yet deep experience in sectors which particularly complement Balderton's investments.
"He has a great knowledge of developing online businesses and the opportunities in digital media. He will be a great addition to our team as we continue to invest in the most innovative and fastest growing companies."