His original name is Thianracha. His initial biography is unclear, evidence of his family appears in the Royal Chronicles stating that "he is royal family of King Chairathirat" and in Sangitiyavansa, the Pali literature in Rattanakosin era stating that he is nephew, son's sister of King Chairachathirat, the evidence in Fernão Mendes Pinto's record states that he is naturall brother's King Chairachathirat. Thianracha joined his brother in the campaigns against Lanna and, in 1546, led the siege ofChiang Mai. Chairacha died in 1546 and his son, Prince Kaewfa succeeded to the throne as King Yodfa, with his mother Sisudachan as regent. She had Yodfa killed in 1548 and eventually put her paramour on the throne as Khun Worawongsathirat. Before doing so however, Thianracha was her co-regent, but wishing to remain faithful to his wife Sri Suriyothai, he became a monk to the Queen Mother's amorous advances. "A band of brothers", retired officers, led by Khun Piren staged a counter-coup, killing Worawongsathirat and Si Suda Chan. Phiren Thorathep then elevated Prince Thianracha to the throne as Phra Maha Chakkraphat.
Upon Maha Chakkraphat's ascension, King Tabinshweti of the Burmese Dynasty of Toungoo marched to Ayutthaya, trying to take advantage of the upheavals in the Siamese capital. The Burmese armies stopped near Ayutthaya. Tabinshweti came with his best general, the UparajaBayinnaung, Viceroy of Prome and Governor of Bassein. Maha Chakkraphat also took to the battleground his whole family, including Sri Suriyothai, the UparajaPrince Ramesuan, and Prince Mahinthrathirat. At Pukaothong field, Maha Chakkraphat fought the Elephant Battle against the Viceroy of Prome but his elephant was overcame and ran away. Sri Suriyothai then rushed to rescue her husband but was slashed to death by the viceroy. The two princes then forced the viceroy to retreat. The Siamese then put a culverin on a barge and sailed along the Chao Phraya to fire the enemies. The mission worked, the Burmese armies retreated but later they ambushed at Kamphaeng Phet the Siamese troops led by Prince Ramesuan and Maha Thammarachathirat. The Burmese held the two in captivity until Maha Chakkraphat gave up two male war elephants in exchange for his son and Maha Thammarachathirat.
After the war of 1548, Maha Chakkraphat insisted on battling Burmese armies near Ayutthaya, so he heavily fortified the city and de-fortified three nearby cities, Suphanburi, Lopburi and Nakhon Nayok in order to prevent the Burmese from taking them as bases. The census was taken to derive all available manpower for war. Wild elephants were caught and accumulated in the full-scale preparation for war. Bayinnaung became King after the death of Tabinshwehti, and upon hearing about the white elephants, requested two. As Maha Chakkraphat refused, the Burmese King marched to Ayutthaya with a large army. His route was via the northern provinces since he had conquered the Lanna in 1558 and occupied Chiang Mai. Phraya Sukhothai and Phra Maha Thammaracha surrendered when Sukhothai and Phitsanulok were captured. The governors of Sawankhalok and Phichai submitted without resisting. At Chainat, Bayinnaung clashed with Prince Ramesuan's army but was able to break through. The Burmese army then reached Ayutthaya and laid siege, bombarding the city so immensely that Maha Chakkraphat "agreed to come to friendly relations with His Majesty of Hongsawadi." Additionally, he paid tribute of four white elephants and Phra Ramesuan, Phraya Chakri and Phra Songkhram were brought back to Pegu as hostages. At Pegu, King Maha Chakkraphat entered the monkhood. Though Damrong Rajanubhab asserts the king only entered the monastery after his daughter Phra Thepkasattri was kidnapped by the Burmese, giving up his throne in dishonor. He resumed his regal powers at the urging of his son Mahinthrathirat.
Second Reign
In early 1568, the captive king successfully convinced Bayinnaung to allow him to go back to Ayutthaya on pilgrimage. Upon his arrival, in May 1568, he disrobed and revolted. He also entered into an alliance with King Setthathirath of Lan Xang. He was not able to convince Maha Thammarachathirat of Phitsanulok to join him and his son in the revolt. Thammarachathirat remained loyal to Bayinnaung and survived the siege by Ayutthaya and Lan Xang forces until October when the relief forces from Pegu arrived. The invasion armies laid the Third Siege of Ayutthaya in December 1568. According to Wyatt, Maha Chakkraphat died one month into the siege in January 1569. According to Prince Damrong, he died sometime during the siege. The Burmese chronicles say that the king died on 15 April 1569.