It makes sense. To become the pope, you probably need to be a priest first, right?
Surprisingly, the answer isn’t that simple!
According to the Code of Canon Law, the only requirement to becoming pope is being a baptized Catholic male.
“A baptized male alone receives sacred ordination validly.” – CCL 1024
It’s happened before too. One time in 827 AD, a pope was elected without first being ordained a priest.
Pope Valentine showed an early aptitude for learning from a young age and went to live at a school attached to the Lateran Palace. He was made a deacon by Pope Paschal I sometime around 817 to 824 AD.
For his “piety and purity of morals,” he won the favor of the pope and earned the rank of archdeacon. Valentine was also favored by Pascal’s successor, Eugene II.
After Eugene II’s death, Valentine was acclaimed as pope by the Roman clergy, nobility, and citizenry. He initially refused, and had to be taken from the Basilica di Santa Maria Maggiore and installed in the Lateran Palace.
In their haste, he was enthroned pope before he was ordained a priest. The following Sunday, he was consecrated as bishop in Saint Peter’s Basilica.
However, no representatives from the Holy Roman Empire were present, and he had no opportunity to certify his election as pope with King Louis the Pious as his papacy ended in just five weeks with his death on October 10th in 827.
A non-priest pope hasn’t happened since 1379.
Since then, every pope has been selected from the College of Cardinals.