In his company he then went to Rome, was there admitted into the Society of Jesus, and was eventually sent to Clermont College, Paris, in June, 1567, where Hay had become rector; and remained there in various posts, e.g. professor, head of the Scottish Jesuit Mission (1585), till 1590.
In 1585 he was summoned to Rome as the representative of France on the Committee of Six, who eventually drew up Claudio Acquaviva's first edition of the "Ratio Studiorum", printed in 1586.
After the Duke of Parma had revictualled the town (September), Tyrie was again sent to Rome, as French deputy for the congregation, which finally supported the government of Acquaviva.
On his return in December, Tyrie was sent to the University of Pont-à-Mousson, as professor of Scripture and head of the Scots College, and two years later, on the successive deaths of Edmund Hay and Paul Hoffaeus, he was again called to Rome (22 May 1592), where he became Assistant for France and Germany, and played his part in the Sixth General Congregation of the Society of Jesus (1593).
The earls asked and obtained a subsidy from Pope Clement VIII; and Tyrie's advice and opinion were constantly taken by both the papal and the Scottish negotiators.