So, when was the last time a non-Cardinal became a Pope? Never?
Pope Alexander was a priest for one day and they made him pope. Very interesting guy ~ rather like a combination arbitrage manager, mafia don and guerrilla fighter who could also sail a ship, read, write, and more or less start sticking a small country together.
There have been 6, the last being Urban VI who was Pope from 1378 until 1389. If that seem distant, consider that the last Pope to resign did so in 1415.