He came to power by helping his brother Byattaba stage a coup against King Binnya U.
He was also a key figure who started the Ava–Hanthawaddy War (1385–1391) between the Mon-speaking Hanthawaddy Pegu and the Burmese-speaking Ava.
Laukpya was appointed governor of Myaungmya, a key port in the Irrawaddy delta by King Binnya U.
In 1384, the brothers refused to extend the same recognition to Binnya U's son and successor Razadarit.
Razadarit's army could not take Myaungmya, which was heavily fortified, and was defeated at Bassein which was defended by Laukpya's two sons.