The two seats in Uttar Pradesh fell vacant after Chief Minister Yogi Adityanath and Deputy Chief Minister Keshav Prasad Maurya resigned from the Lok Sabha following their appointments last year.
The choice of Upendra Shukla is seen as an outreach by the party to Brahmins, who are the largest upper caste community in the state and have been its traditional supporters.
The party also announced its candidates in Bihar, naming Pradeep Singh as its nominee for the Araria Lok Sabha by-poll and Rinki Pandey for the Bhabua assembly by-election.
Pradeep Singh, a former Araria MP, had lost to RJD’s Taslimuddin in 2014.
The by-elections are scheduled to be held on March 11.