Lenny is now known as Pius XIII. He is the newly elected Pope and former Archbishop of New York.
It has been hinted in the show multiple times that Lenny might be a woman.
Lenny lost both his parents at a young age. He was raised by Sister Mary whom he regarded as his adoptive mother. Lenny's actions show his affection for his father. When he meets her for the first time, he is holding a pipe his father gave him and explains that his father told him to keep it with him always. Many years later, after he has ascended to the papacy, Lenny still keeps the pipe on his person.
"I've been training my whole life to be an invisible pope."