Congress President Rahul Gandhi approved his name which was proposed by observers appointed by the party.
"Congress President Rahul Gandhi has approved the name of Mukesh Agnihotri as the leader of Congress Legislature Party of Himachal Pradesh," AICC general secretary Janardan Dwivedi said in a statement.
He said the observers proposed his name after consulting members of the Congress Legislature Party in the state.
Agnihotri, a four-time legislator, is a confidant of former chief minister Virbhadra Singh and represents the Haroli constituency in Una district of the state.
The Congress could bag only 21 of the 69 assembly seats in the state, with the BJP winning 44.