In Northern Ireland he supported "mixed" (i.e., Catholic and Protestant) child education. In 1991, he gave £8m to the Integrated Education Fund,[20] a grant-making charitable body which aims "to make integration, not separation, the norm in our education system".[21] Queens University Belfast also received grants of more than £100m,[20] for capital projects, child education and medical research.[22]

More controversially, Feeney gave substantial personal donations to Sinn Féin, a left-wing Irish nationalist party that has been historically associated with the IRA.[14] Following the IRA ceasefire in 1994, he funded the party's office in Washington D.C.[20]

Feeney supported the modernization of public-health structures in Vietnam,[18] AIDS clinics in South Africa, Operation Smile's free surgeries for children with cleft lips and palates, earthquake relief in Haiti, and the UCSF Medical Center at the University of California at San Francisco.[8]

Jim Dwyer wrote in The New York Times that none of the one thousand buildings on five continents that were built with Feeney's gifts of $2.7 billion bear his name.[1]

On September 14, 2020, Feeney closed down the Atlantic Philanthropies after the non-profit accomplished its mission of giving away all of its money by 2020.[25]

Immensely based