John Templeton Jr, philanthropist and president of the John Templeton Foundation who worked to advance research into science and philosophy, has died aged 75.

The former paediatric surgeon died at home in Bryn Mawr, Pennsylvania on Saturday, but the announcement was withheld until after the award ceremony for the winner of this year's Templeton Prize, John Vanier founder of L'Arche, on May 18 in London.

Templeton Jr, known as 'Jack', retired from medical practice in 1995 in order to run the foundation established by his father, who had a vision to acquire "new spiritual information" through investing in research. Sir John Templeton, a global investor, set up the Templeton Fund in 1954 and the Foundation in 1987. His son became chairman after Sir John's death in 2008 and during his 20 years at the helm, the endowment grew from $28 million to $3.4 billion.

Templeton's daughter, Heather Templeton Dill, said he had died from cancer.

The Templeton Foundation aims to invest in research that tackled 'life's big questions'. It is most well-known for the Templeton Prize – an annual award worth £1.1 million (about $1.7 million or €1.5 million) given for "exceptional contributions to affirming life's spiritual dimension." Previous winners include Mother Teresa, Desmond Tutu, the Dalai Lama and Billy Graham.

The organisation has faced criticism from some for the kind of research that it supports. Most recently, prominent philosopher Daniel Dennett, co-director of the Center for Cognitive Studies at Tufts University, said he would boycott the World Science Festival taking place next week because it is funded by the Templeton Foundation.

Dennett, who is an atheist, said an interview with Religion News Service that the foundation was "sponsoring some very fine science with no strings attached and then using their sponsorship of that to try and win prestige for other projects that are not in the same league."

John Marks Templeton was born in New York City in 1940, he studied history at Yale and graduated in 1962. He then studied medicine at Harvard, having been influenced by a Presbyterian medical mission trip to Cameroon in 1960. He graduated in 1968 and in 1970 married his wife Josephine, who was paediatric anaesthetist. He spent much of his medical career working at the Children's Hospital of Philadelphia, where he gained an international reputation for his work with conjoined twins.

An evangelical Christian, Templeton served on many boards including the Becket Fund for Religious Liberty and the National Bible Association. He was a member of Proclamation Presbyterian Church in Bryn Mawr.

In addition to publishing his medical research, he published two books, Thrift and Generosity: The Joy of Giving (2004) and an autobiography, John M. Templeton, Jr.: Physician, Philanthropist, Seeker (2008).

He is survived by his wife, their two daughters and six grandchildren.