The former MLA was sitting in the courtyard of the government accommodation allotted to his wife in Bilapsur along with others celebrating Holi when four people came and opened fire.
Thakur received a bullet in his leg.
A manhunt has been launched to catch the culprits who reportedly ran on foot towards the main market, SP Bilapsur Sandeep Dhawal told the PTI. The accused would be nabbed soon and booked under relevant sections of law, he added.
Immediately after the attack, Thakur was referred to Indira Gandhi Medical College, Shimla while the PSO was rushed to the AIIMS Bilaspur.