Andy Williams will work in the British Embassy in Washington advising British cyber security companies on how to promote their products in the US.
Mr Williams started his career with BT before moving into security software.
He spent five years working for the US government as its international trade advisor to US IT security firms.
Mr Williams will take up the post in April.
He said: "This role will involve working with UK and US business and government to help boost transatlantic cyber security deals in support of the UK's aim to achieve Â£2bn in cyber security exports by 2016.
"The US currently represents the largest global market for cyber security at over $40bn (Â£26.4bn) and this market is expected to grow to over $60bn (Â£39.5bn) by 2019."
The appointment was one of a series of measures to help UK businesses tackle cyber security challenges and came as Prime Minister David Cameron met US President Barack Obama in Washington, with cyber security on the talks' agenda.
An online security expert originally from Swansea has been appointed as the first UK cyber envoy to the United States.