In his first season, he helped his team finish fourth in 2018 Myanmar National League as well as claiming a second place in 2018 General Aung San Shield.

2020 was a successful year for Hein Htet Aung as he helped Hanthawaddy United finish second in 2020 Myanmar National League, which was the biggest achievement in club's history.

After a successful 3 years spell at Hanthawaddy United, scoring a total of 9 goals over 62 appearances, Hein Htet Aung has decided to part ways with the team in order to achieve his dream of playing abroad.

On 13 August, his agent confirmed he has sign a new contract before his amazing performance against Kedah Darul Aman that he managed got two assist in 4–2 win.

[3][4] On March 6, 2021, after a match between Selangor II and PDRM FC, Hein displayed a three-finger salute showing solidarity for the ongoing Myanmar protests.