Philip Livingston was a Presbyterian.
He was identified as a Presbyterian by the Presbyterian Historical Society. (Source: Ian Dorion, "Table of the Religious Affiliations of American Founders", 1997).
From: B. J. Lossing, Signers of the Declaration of Independence, George F. Cooledge & Brother: New York (1848) [reprinted in Lives of the Signers of the Declaration of Independence, WallBuilder Press: Aledo, Texas (1995)], pages 67-68:
Among the brilliant names of the Revolutionary era, none shine with a purer lustre, than that of Livingston. Like the name of Wolcott, from the early settlement of our country to the present time, that name has been conspicuously honored, and has held a large place in the public esteem.From: Robert G. Ferris (editor), Signers of the Declaration: Historic Places Commemorating the Signing of the Declaration of Independence, published by the United States Department of the Interior, National Park Service: Washington, D.C. (revised edition 1975), page 96-98:
Philip Livingston was descended from a Scotch minister of the gospel, of exemplary character, who, in 1663 left Scotland and settled in Rotterdam, where he died. His son Robert (the father of [Philip Livingston]) soon after his father's decease, emigrated to America... He had three sons, of whom Philip was the oldest, and who became, on the death of his father, heir to the manor.
A member of the landed gentry, merchant Philip Livingston lived a princely life and devoted much energy to civic affairs and philanthropic enterprises...
Livingston was the fifth son of Philip Livingston, second lord of Livinston Manor, of Scotch descent, and Catherine Van Brugh, of Dutch lineage. Young LIvingston was born in 1716 at his father's townhouse in Albany and spent most of his childhood there or at the family manor in Linlithgo...
Livingston passed away at the age of 62 in 1778, the third earliest signer to die (after John Morton and Button Gwinnett). At the time, though in poor health, he was still in Congress, then meeting at York, Pa. He is buried in Prospect Hill Cemetery in that city.