Singhdeo, a five-time MLA from Patnagarh assembly segment in Bolangir district, said he would take up the job with all sincerity.
Singhdeo had, however, earlier opined that the leader of the BJP legislature party be given to any new person.
But BJP President Amit Shah recommended his name for the post.
The MLA from Patnagarh, Singhdeo had been the leader of BJP legislature party in the 14th Assembly.
The BJP has 10 MLAs in the 147 member House.