Are any canonized saints known to have passed through purgatory before entering heaven?
The Church is silent on whether or not canonized saints have experienced some level of purgation. Canonization simply means that the Church knows for certain that particular individuals are now in heaven; it does not consider whether they experienced purgatory before they arrived in heaven. It is possible that canonized saints go directly to heaven; it is also possible that they experience purgatory.
Although the Church has not stated whether saints experience purgatory, we do know of at least one saint who thought that purgatory might be a possibility for her despite her firm belief that heaven was her eternal destiny. St. Therese of Lisieux (1873-1897) – who was told by her confessor that she had never committed a mortal sin, who believed that purgatory was not absolutely necessary for a soul who allows God to purify him at every moment of this life, and who is famous for her declaration, “I will let fall from heaven a shower of roses” – once said the following:
Oh, if you only knew how sweet my judgement will be! But even if the good God punishes me a bit, I will find even that sweet. If I go to purgatory, I will still be very content, I will behave like the three Hebrews, I will walk about in the furnace singing the song of love. Oh, how happy I would be, if there I could deliver other souls, suffer in their place; then I would do well, I would deliver the captives! (Last Conversations, July 8, 1897, source).
In short, we do not know if saints eventually canonized by the Church pass through purgatory, but a soul’s having been in purgatory does not bar him from canonization.
Teaching of St. Therese of Lisieux on Purgatory** by Fr. Hubert van Dijk, O.R.C.