Halley was born in Coolnagour in 1782. In September 1817 Halley enrolled in S. Patrick's College, Carlow where he remained until July 1818. He then went to Maynooth and was ordained in 1822.  On 19 February 1838 Halley was appointed Parish Priest to Dungarvan. He lived in Bridge Street. The house is now part of Lawlor's Hotel. Fr. Halley was very active during the Famine period. Under the Public Works Relief scheme, he instigated the construction of a road between Two Mile Bridge and Clashmore, as well as several bridges. The purpose of the construction was to provide employment. A limestone plaque was placed on one of the bridges with the following inscription: Very Revd. J. Halley P.P. Dungarvan Caused this road and these bridges to be executed In the year of the Famine 1847.

He was appointed chairman of the electoral division committee and also chaplain to the workhouse. In December 1871 a row developed between him and the Guardians. The Guardians had recommended that the Catholic and Protestant chaplains to the workhouse should get a rise in salary. Halley declined the increase because the Union finances would not be able to cover it. He was critical also due to the fact that the Guardians themselves were looking for an increase. He suggested that they should resign if they were unhappy with their salaries. Halley remained as P.P. in Dungarvan until his death in 1875. A memorial stone to him at St. Mary's Parish church is inscribed: Pray for Very Rev. Jeremiah Halley, Parish Priest of Dungarvan who died on Christmas Eve 1875, in the 83rd year of his age, after he had laboured as Pastor for 35 years as curate in Dungarvan.