He was ordained to the priesthood by Bishop Adrianus Godschalk[1] on June 15, 1889, and then traveled to the United States at the request of Archbishop Francis Janssens, who assigned Drossaerts to pastoral work in Lake Charles, Louisiana.

He initiated the religious education of African-American Catholics,[2][3] and also served as a pastor in New Orleans, Broussard, and Baton Rouge.

He received his episcopal consecration on the following December 18 from Archbishop Giovanni Bonzano, with Bishops Theophile Meerschaert and John Marius Laval serving as co-consecrators, in St. Louis Cathedral.

[citation needed] Throughout his tenure in San Antonio, he provided refuge to numerous clergymen who fled from persecution during the Mexican Revolution, raising over $21,000 for this cause in 1926–1929.

[4] At the funeral Mass for the late Bishop of Aguascalientes, Drossaerts condemned the perceived lack of American interest in the Church's persecution in Mexico, saying, "Liberty is being crucified at our very door, and the United States looks on with perfect indifference.