We dont know much about Juniper before he joined the friars in 1210. Francis sent him to establish "places" for the friars in Gualdo Tadino and Viterbo. When St. Clare was dying, Juniper consoled her. He was devoted to the passion of Jesus and was known for his simplicity.
Several stories about Juniper in the Little Flowers of St. Francis illustrate his exasperating generosity. Once Juniper was taking care of a sick man who had a craving to eat pigs feet. This helpful friar went to a nearby field, captured a pig and cut off one foot, and then served this meal to the sick man. The owner of the pig was furious and immediately went to Junipers superior. When Juniper saw his mistake, he apologized profusely. He also ended up talking this angry man into donating the rest of the pig to the friars!
Another time Juniper had been commanded to quit giving part of his clothing to the half-naked people he met on the road. Desiring to obey his superior, Juniper once told a man in need that he couldnt give the man his tunic, but he wouldnt prevent the man from taking it either. In time, the friars learned not to leave anything lying around, for Juniper would probably give it away.
He died in 1258 and is buried at Ara Coeli Church in Rome.