He was appointed Referendary of the Tribunals of the Apostolic Signatura of Justice and of Grace and proved himself a capable administrator.
He was named Governor in a succession of comunes and towns including:[1] Terni (1626), Cesena (1627–1628), Orvieto (1628–1629), Camerino (1630), Ancona (1631–1633), and Viterbo (1633–1634).
He was elevated to cardinal by Pope Urban VIII in 1643 and was made Cardinal-Priest at the Basilica of Santi Bonifacio e Alessio that same year.
Theodoli was elected Bishop of Imola in 1644 and was consecrated by Cardinal Ciriaco Rocci, Cardinal-Priest of San Salvatore in Lauro, with Alfonso Gonzaga, Titular Archbishop of Rhodus and Giacomo Theodoli, Bishop of Forlì, serving as co-consecrators.
[2] he resigned the government of the diocese because of ill health in 1646 and was transferred to the Church of Santa Maria del Popolo which housed the Theodoli family chapel.