Udai Singh was born in Chittor. In August 1522. after the death of his father, Maharana Sangram Singh, he was succeeded by his eldest surviving son, Maharana Ratan Singh. Ratan Singh was assassinated in 1531. He was succeeded by his brother Maharana Vikramaditya Singh. During his reign, when the Turkic Sultan of Gujarat Bahadur Shah sacked Chittor in 1534, Udai Singh was sent to Bundi for safety. In 1537, Banbir killed Vikramaditya and usurped the throne. He tried to kill Udai Singh also, but Udai's nurse Panna Dhai sacrificed her own son Chandan to save him from his uncle Banbir and took him to Kumbhalgarh. She did not ask for anything in return either. She started living in Bundi and did not allow Udai Singh to come and meet her. He lived in secret in Kumbhalgarh for two years, disguised as a nephew of the governor Asha Shah Depura(Maheshwari).
In 1540, he was crowned in Kumbhalgarh by the nobles of Mewar. His eldest son Maharana Pratap from his first wife, Maharani Jaivantabai Songara (daughter of Akhey Raj Songara of Jalore), was born in the same year. He had twenty two wives and over 56 sons and 22 daughters. His second wife, Sajjabai Solankini gave birth to his son Shakti, Sagar Singh and Vikram Dev. Dheerbai Bhattiyani was his favourite wife and was the mother of his son Jagmal Singh and daughters Chand Kanwar and Maan Kanwar. His fourth wife was Rani Veerbai Jhaala daughter of Rana Jaith Singh of Kherwa.
In 1562, he gave refuge to Baz Bahadur of Malwa. Using this as a pretext, Akbar attacked Mewar in October 1563. On 23 October 1567 Akbar formed his camp near Udaipur.According to Kaviraj Shyamaldas, Udai Singh called a council of war. The nobles advised him to take refuge along with the princes in the hills, leaving a garrison at Chittor. Udai Singh retired to Gogunda (which later became his temporary capital) leaving Chittor in the hands of his loyal chieftains Jaimal and Patta. Akbar captured Chittor after a long siege on 25 February 1568. He later shifted his capital to Udaipur. He died in 1572 in Gogunda. Before his death, he nominated his fourth son Jagmal as his successor under the influence of his favourite queen and Jagmal's mother Rani Bhattiyani. But after his death, the nobles of Mewar prevented Jagmal from succeeding and placed Maharana Pratap Singh on the throne on 1 March 1572.