The Very Rev. James Parks Morton, who in 25 years as dean of the Cathedral Church of St. John the Divine in Upper Manhattan transformed it from a religious backwater into a vibrant center for the arts, the homeless, circus performers, household pets, endangered animals and interfaith engagement, died on Saturday at his home in Manhattan. He was 89.

His death was confirmed by his daughter Polly Morton Barton. She said he had been treated for Alzheimer’s disease.

St. John the Divine, the seat of the Episcopal diocese of New York, sits on a 13-acre campus in Morningside Heights. It is said to be the largest Gothic cathedral in the world and one of the biggest church buildings anywhere.

Mr. Morton was appointed dean in 1972 by the new bishop of the diocese, the Rev. Paul Moore Jr. Together they re-envisioned the church as “a medieval cathedral for New York City” that would engage the city in all its promise and problems.