Sharpe will start on 14 April, reporting to managing editor Stig Abell, and will replace Emily Coen, who is understood to be joining the communications team at British Airways.
Sharpe said his brief is to push out the Sun's campaigns and exclusives further afield, with the aim of attracting more readers to the newspaper’s online content and the physical paper.
"I have spent my career working closely with newspapers, so I feel very privileged at the prospect of becoming a small part of the biggest title in the UK," he said.
Sharpe joins from Business for Britain, an organisation campaigning on behalf of businesses for a renegotiation of the UK’s role in Europe. He was previously head of press on the NO to AV campaign, campaign director at Big Brother Watch and head of media at The Countryside Alliance.
He has worked in PR and corporate affairs for various London consultancies, including Pagefield, and was a press officer on Boris Johnson’s 2008 London Mayoral campaign.