In 1262 Leo married Keran (Kir Anna), the daughter of Prince Hethum of Lampron.
In 1266 Leo was captured and his younger brother Thoros killed while fighting the Mamluk invaders. Leo was ransomed by his father, who gave up the throne for him shortly after. He was known as a pious king, devoted to Christianity.
In 21 years of marriage Leo had 15 children by his wife Keran, eight sons and seven daughters. Two sons and two daughters died at an early age:
Hethum II (ruled 1289 to 1293, 1294 to 1297, 1299 to 1307)