While Dr Liezietsu polled 8026, his only rival independent opponent Kekhrie Yhome got 4558 votes.
In the 23 postal ballot, Dr Liezietsu got 12, Yhome 10 and 1 was rejected.
The bye-election was necessitated following the resignation of sitting MLA Khriehu Liezietsu on May 24 last, so that his father Shurhozelie Liezietsu could get elected as a member of the state Assembly.
Liezietsu had become the chief minister in February, 2017 replacing NPF colleague TR Zeliang, who again ousted him in a rebellion on July 19 last.