He contributed widely to scholarly journals and was the author of several books and monographs on the history of Catholicism in the United States.
[1] From an early age, Griffin became known as a regular contributor and editor with various Catholic publications.
[1] In 1872, he was made secretary of the Irish Catholic Benevolent Union, and both founded and edited its journal from 1873 to 1894.
Articles on American Catholic history were a regular feature in his journal.
Griffin also published monographs on the history of Old St. Joseph's and several other Philadelphia churches (1881–1882), on Bishop Michael Francis Egan, O.S.F.