Singh has won the Bihar Assembly elections 2020 from Karakat constituency, securing 79,224 votes.

He was able to defeat his nearest political rival and the runner-up candidate from this constituency, Rajeshwar Raj of Bhartiya Janata Party with a margin of 16,548 votes.

Singh is a political activist as well and he has also contested Bihar Assembly elections earlier in 2010, but was defeated by Rajeswar Raj, who was then a member of Janata Dal (United).

[2][3][4][5] Arun Singh, who is a left wing politician, is a three time Member of Legislative Assembly from the Karakat constituency.

In 2010 Bihar Assembly elections, he was defeated by Janata Dal (United) candidate Rajeswar Raj.