Besides his popularity, John was able to keep his personal profile low and secret. It was believed that he was married to love of his life but the name of his wife is unknown in the media. His nationality is American and he was of white ethnicity.
While John was in Philadelphia, he attended several private schools. At the later stage of his life, he moved to Paris. There he got enrolled at Ecole des Arts Decoratifs and the Ecole des Beaux Arts. In 1904, he began working for Carrère and Hastings. During his time, he was also a member of American Institute of Architects. He also served as the chairman of the Public Information Committee. He is known for his architectural work in Our Lady of Mercy School, Residence of Newton Fassett, Our Lady of Victory Church and many more. He is also a talented writer and an author. In 1913, he published his first book The Essentials of Composition as Applied to Art. He is also known for being a writer of Masterpieces of Spanish Architecture. His annual salary and net worth was high.