Why Is Blessed Paul VI’s Feast Day His Birthday?

You are correct. The Church only formally celebrates the birthdays of three people in the liturgical calendar: John the Baptist (June 24), the Blessed Mother (September 8) and Jesus (December 25). And there are other feast days honoring each of these persons.

Often, but not necessarily, a feast day is a saint’s “birthday into eternal life,” i.e., the day the saint died. St. Maximilian Kolbe is an example (August 14). In the case of Blessed Paul VI, it just happens that his feast day is also his earthly birthday. To be clear, his feast day is not a celebration of his earthly birthday, as it is in the case of Jesus, the Blessed Mother and St. John the Baptist. It’s a celebration of him and his life in general.