Théophile Meerschaert was born on 24 August 1847 in Russignies, a farming village near Renaix, in the province of East Flanders in Belgium.

He was the eighth of nine children[1] of the peddler from Renaix, Pierre François Meerschaert, and his wife from Russeignies, Marie Therèse Gabreau.

He became vicar general of the Diocese of Natchez on 18 April 1887, and later apostolic administrator (1888–1889) after Bishop Francis Janssens was promoted to Archbishop of New Orleans in 1888.

[1] On 2 June 1891, Meerschaert was appointed Vicar Apostolic of Indian Territory in Oklahoma and Titular Bishop of Sidyma by Pope Leo XIII.

[5] He received his episcopal consecration on the following 8 September from Archbishop Janssens, with Bishops Edward Fitzgerald and Thomas Heslin serving as co-consecrators, at St. Mary's Cathedral.