The Greatest Kushan leader who got converted to Buddhism was

Kanishka was a great patron of the Buddhist faith; Buddhism spread to Central Asia and the Far East across Bactria and Sogdia, where his empire met the Han Empire of China. King Kanishka was greatly influenced by the knowledge, teachings and personality of the Buddhist scholar Asvaghosha so, he decided to embrace Buddhism in later days of his life. He even accepted the Mahayana sect of Buddhism as his state religion.