According to the medieval Persian historian Muhammad ibn Jarir al-Tabari, Yazid came to power on the death of Umar II on February 10, 720. His forces engaged in battle the Kharijites with whom Umar had been negotiating. After initial setbacks, Yazid's troops prevailed and the Kharijite leader Shawdhab was killed. Yazid ibn al-Muhallab had escaped confinement on the death of Umar. He made his way to Iraq. There he was much supported. He refused to acknowledge Yazid II as caliph and led a very serious uprising. Initially successful, he was defeated and killed by the forces of Maslamah ibn Abd al-Malik.
Numerous civil wars began to break out in different parts of the empire such as in the Al Andalus (the Iberian Peninsula), North Africa and in the east. In A.H. 102 (720-721) in Ifriqiyah, the harsh governor Yazid ibn Muslim was overthrown and Muhammad ibn Yazid, the former governor, restored to power. The caliph accepted this and confirmed Muhammad ibn Yazid as governor of Ifriqiyah.
Al-Jarrah ibn Abdallah, Yazid's governor in Armenia and Adharbayjan, pushed into the Caucasus, taking Balanjar in A.H. 104 (722-723). That same year Yazid's governor in Medina, Abd al-Rahman ibn al-Dahhak, incurred the caliph's displeasure because the governor was exerting undue pressure trying to force a woman to marry him. She appealed to Yazid who replaced Abd al-Rahman with Abd al-Walid ibn Abdallah.
The Byzantine chronicler Theophanes the Confessor states that a wizard advised Yazid that he would reign for forty years, if he opposed Christian icons. Yazid did so, but died the same year he issued his iconoclastic decree. Anti-Umayyad groups began to gain power among the disaffected. Al-Tabari records that Abbasids were promoting their cause in A.H. 102 (720-721). They were already building a power base that they would later use to topple the Umayyads in CE 750.
An anecdote told of Yazid is that his wife Sudah learning he was pining for an expensive slave girl, purchased this slave girl and presented her to Yazid as a gift. This woman's name was Hababah and she predeceased Yazid (at Tabari v. 24, p. 196). It is said that, while feasting with Hababah, Yazid threw a grape into her mouth, on which she choked and died in his arms. Yazid died the next week.
Yazid II died in 724 of tuberculosis. He was succeeded by his brother Hisham.