Sharma's unanimous election as the state unit chief was announced by Kalraj Mishra, a senior BJP leader.
No one else had filed nomination for the post, party leaders said.
Sharma, hailing from Mahendergarh, had served as Public Health minister from 1987 to 1990 and Education minister from 1996 to 1999.
He was also the state BJP president from 1990 to 1993.