Ramsay will leave his role as multi-brand marketing director for EE, BT and BT Sport to take up the job of running what the government describes as its most successful international campaign to date.
In September last year the government said the GREAT campaign, launched in 2011, had resulted in a £3.4bn return over the previous seven years.
The campaign, which appears in more than 140 countrues, was devised to showcase the UK and encourage people to visit, do business, invest and study here.
DIT said the campaign had won 69 national and international awards to date, and the brand was recently valued at £271m.
As the UK prepares to leave the EU, the campaign could be a critical factor in the country's future economic success.
Earlier this week, the GREAT campaign turned its attention to the UK's fashion industry, with a film starring fashion luminaries Dame Zandra Rhodes and Hilary Alexander OBE, alongside emerging UK talent.
Ramsay takes over from Claire Pimm, deputy director for campaigns, insight and evaluation at the Prime Minister's Office and Cabinet Office, who was appointed interim director of the 'GREAT Britain' campaign in June.
Conrad Bird, the architect of the campaign, who led it from its inception as director, left the role earlier this year.
The DIT's permenant secretary, Antonia Romeo, said Ramsay brings "significant marketing and campaigns experience from the private sector into the Civil Service".
Prior to his most recent role, Ramsay was at BT for 12 years as its consumer marketing director and launched the subscription TV service BT Sport.
He was responsible for one of the UK's biggest media budgets, according to DIT, and oversaw BT's advertising and comms.
Earlier in his career, Ramsay worked for Barclays bank for eight years, rising to the role of strategy manager.
In his new job, Ramsay will report to DIT's director of comms, Toby Orr.
Ramsay said: "I am honoured to be leading such a prestigious and high-profile campaign that makes such a massive difference to our nation. The opportunity to promote and grow a very special brand – the UK itself – means this is a truly unique marketing role."
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