Whelan was born in Kilkenny, Ireland, and moved with his parents to the United States at age 10 or 12, settling in New York.

[2] Whelan requested the Dominican Sisters of St. Mary in Somerset establish a school in his diocese.

On September 23, 1863, Pope Pius IX accepted the resignation and on February 12, 1864, appointed him as Titular Bishop of Diocletianopolis in Palaestina.

[2] Whelan briefly retired to St. Joseph's Convent before taking up residence at St. Thomas Parish in Zanesville, Ohio.

[1] He devoted his time to theological, historical, and chemical studies, and published a defense of papal infallibility in 1871.