Restless in his life as a teacher and determined to be a missionary, the young Abbé Brottier joined the Congregation of the Holy Spirit at Orly in 1902.
After completing his novitiate, Brottier was sent by the congregation to serve as a vicar in a mission parish in Saint-Louis, Senegal in 1903.
 He was disappointed that he had been assigned to a city rather than the more difficult interior.

Nevertheless, Brottier immediately set to work.
He gave weekly instructions to secondary school students, founded a center for child welfare, and published a parish bulletin, The Echo of St. Louis.
His health suffered from the climate, however, and he spent a six-month period of convalescence in France in 1906.
In 1911 his poor health would force him to return to France for good.

After his final departure from Senegal, Brottier spent a brief, but personally significant, stay at the Trappist monastery at Lérins—the same island monastery associated with Saint Patrick's preparation for evangelization in Ireland.
Brottier had felt called to a more contemplative life than he had been living as a missionary in Africa, but the stay at Lérins rid him of that idea.
As Brottier wrote to his sisters, "I lived unforgettable hours in the recollection of the cloister in an atmosphere of sacrifice and immolation.
But the lack of sleep, and especially of food, wore me down, and after a few days I had to yield to the evidence: I was not made for this kind of life".

Even after he had left Senegal, Brottier was asked by Bishop Hyacinthe Jalabert, the Apostolic Vicar of Senegal, to conduct a fund-raising campaign to build a cathedral in Dakar.
To this end, Brottier was appointed the Vicar General of Dakar, even though he was residing in Paris.
Brottier focused on this project for seven years over two periods (i.e., 1911–1914 and 1919–1923), the interlude being a result of the First World War.
The so-called "African Memorial Cathedral" was consecrated on February 2, 1936, just a few weeks before Brottier's death.
Restless in his life as a teacher and determined to be a missionary, the young Abbé Brottier joined the Congregation of the Holy Spirit at Orly in 1902. After completing his novitiate, Brottier was sent by the congregation to serve as a vicar in a mission parish in Saint-Louis, Senegal in 1903.  He was disappointed that he had been assigned to a city rather than the more difficult interior.
Nevertheless, Brottier immediately set to work. He gave weekly instructions to secondary school students, founded a center for child welfare, and published a parish bulletin, The Echo of St. Louis. His health suffered from the climate, however, and he spent a six-month period of convalescence in France in 1906. In 1911 his poor health would force him to return to France for good.
After his final departure from Senegal, Brottier spent a brief, but personally significant, stay at the Trappist monastery at Lérins—the same island monastery associated with Saint Patrick's preparation for evangelization in Ireland. Brottier had felt called to a more contemplative life than he had been living as a missionary in Africa, but the stay at Lérins rid him of that idea. As Brottier wrote to his sisters, "I lived unforgettable hours in the recollection of the cloister in an atmosphere of sacrifice and immolation. But the lack of sleep, and especially of food, wore me down, and after a few days I had to yield to the evidence: I was not made for this kind of life".
Even after he had left Senegal, Brottier was asked by Bishop Hyacinthe Jalabert, the Apostolic Vicar of Senegal, to conduct a fund-raising campaign to build a cathedral in Dakar. To this end, Brottier was appointed the Vicar General of Dakar, even though he was residing in Paris. Brottier focused on this project for seven years over two periods (i.e., 1911–1914 and 1919–1923), the interlude being a result of the First World War. The so-called "African Memorial Cathedral" was consecrated on February 2, 1936, just a few weeks before Brottier's death.
Daniel Brottier