Mr Husain, who set up the Quilliam think tank in 2007, will leave the organisation this November to become a senior fellow at the US Council for Foreign Relations (CFR).
He is also planning to take on an academic role at an American university and work on a follow-up book to The Islamist.
In his first book the London-born writer described his five-year involvement with the Islamic fundamentalist group Hizb ut-Tahrir, an experience which led to the formation of Quilliam.
Mr Husain, 34, praised the Quilliam staff as “the most intelligent, brave, visionary and patriotic young people working in Britain.
“It has been a joy and honour to work with them.”
He thanked those in the media and in politics who “strengthen Britain’s national interests by exposing and challenging extremist ideas among Muslim communities both in the UK and further afield.”
Mr Husain said he was looking forward to addressing “the complex problems of extremism” in America.
“The USA is at the forefront of this struggle.”
Quilliam will now be led by Maajid Nawaz, another former member of Hizb ut-Tahrir. Praising the work of his colleague, Mr Nawaz said: “Quilliam’s vast output has contributed to improving civil society debates around terrorism.
"Islamists in Britain are today exposed, discredited, and unable to muster a coherent argument in defence of their confrontational causes, while the majority of normal Muslims are quietly finding harmonious ways in which to respond to the challenges of living in a secular, liberal society.
“Much of this was made possible by Ed Husain. His decision to join CFR makes us proud and will help strengthen transatlantic civil society ties.”