Gilbert Chagoury was born to Lebanese immigrant parents in Lagos, Nigeria. He studied at the Collège des Frères Chrétiens in Lebanon before returning to Nigeria.
In 1971, he co-founded the Chagoury Group with his younger brother Ronald Chagoury, an industrial conglomerate with interests in construction, real estate and property development, flour mills, water bottling and purification, glass manufacturing, insurance, hotels, furniture manufacturing, telecommunications, IT, catering and international financing. Gilbert and Ronald Chagoury founded C & C Construction in the late 1970s, which was the forerunner of Hitech and ITB (these now form the Construction Division of the Chagoury group of Companies).
Through their ownership of the Chagoury Group, Gilbert Chagoury and family have an estimated wealth of $4.2 billion.
He served as an Ambassador and Adviser to governments in Africa and the Americas. He has also served as Ambassador to the Vatican for St. Lucia, economic adviser to President Mathieu Kérékou of Benin, and ambassador to UNESCO.
Chagoury was a close associate of Nigerian dictator, General Sani Abacha, who helped his business interests in the country. After Abacha died in 1998, Chagoury returned an estimated $300 million to the Nigerian government to secure his indemnity from possible criminal charges.
Chagoury has been a supporter of Bill and Hillary Clinton since the 1990s. He has funded their election campaigns and is a major donor to the Clinton Foundation.
In 2010, ABC News reported on the U.S. Department of Homeland Security's apology to Chagoury for his detention at Teterboro Airport for over four hours because of inclusion on a no-fly list.
He is a key benefactor for St. Jude Children's Research Hospital in Memphis, Tennessee, and his private contributions have improved health care and public infrastructure of Miziara, Northern Lebanon, home to both his and his wife's family. He serves on the board of the Lebanese American University where he provided a donation of $10 million to fund the Gilbert and Rose-Marie Chagoury School of Medicine and $3.5 million for the construction of the Alice Ramez Chagoury School of Nursing.
The Louvre's Gilbert et Rose Marie Chagoury Gallery is named for them, housing a permanent exhibit including French works donated by the Chagourys. He has donated in excess of $340,000 for the renovations of the Church of Our Lady of Lebanon in Paris, France. He has also donated US$10,000 to the Beverly Hills 9/11 Memorial Garden in Beverly Hills, California.
He is married to Rose Marie Chamchoum of Miziara in Northern Lebanon since 1969.