Slowly, John came to see that the Catholic Church could embrace all kinds of people. Among these, he noted, were many martyrs. He decided to become Catholic and was received into the Church at Louvain, Belgium, in 1596 at the age of 17.
John continued his studies, first with the Benedictines, then as a student at the Jesuit College at Olmutz. He joined the Jesuits and for the next 10 years underwent their rigorous intellectual and spiritual training. Ordained a priest in France in 1610, he met two Jesuits who had just returned from Scotland after suffering arrest and imprisonment. They saw little hope for any successful work there in view of the tightening of the penal laws. But a fire had been lit within John. For the next two and a half years he pleaded to be missioned there.
Sent by his superiors, he secretly entered Scotland posing as a horse trader or a soldier returning from the wars in Europe. Unable to do significant work among the relatively few Catholics in Scotland, John made his way back to Paris to consult his superiors. Rebuked for having left his assignment in Scotland, he was sent back. He warmed to the task before him and had some success in making converts and in secretly serving Scottish Catholics. But he was soon betrayed, arrested and brought before the court. His trial dragged on until he had been without food for 26 hours. He was imprisoned and deprived of sleep. For eight days and nights he was dragged around, prodded with sharp sticks, his hair pulled out. Still, he refused to reveal the names of Catholics or to acknowledge the jurisdiction of the king in spiritual affairs. He underwent a second and third trial but held firm. At his final trial he assured his judges: "In all that concerns the king, I will be slavishly obedient; if any attack his temporal power, I will shed my last drop of blood for him. But in the things of spiritual jurisdiction which a king unjustly seizes I cannot and must not obey."
Condemned to death as a traitor, he was faithful to the end, even when on the scaffold he was offered his freedom and a fine living if he would deny his faith. His courage in prison and in his martyrdom was reported throughout Scotland.
John Ogilvie was canonized in 1976, becoming the first Scottish saint since 1250.