Mr Dhiman is the son of BJP stalwart and former minister Ishwar Dass Dhiman, who won the seat six consecutive times since 1990. He made his electoral debut when the seat fell vacant following the death of the former minister in November last year.
Mr Dhiman polled 24,453 votes against the 16,144 votes polled by Promila Devi. Pawan Chandel, a BJP rebel who contested as an Independent, polled 4,630 votes.
The BJP has emerged as the big winner in the latest round of by-elections across eight states. It has won in four seats and is leading in two of the 10 seats where polling was held.
The party has wrested the Rajouri Garden seat from the ruling Aam Aadmi Party ahead of the coming civic elections in Delhi. In Rajasthan, it has won the Dholpur seat from Mayawati's BSP.
In Shivraj Singh Chouhan's Madhya Pradesh, it has won Bandhavgarh and is leading in Ater. In Assam, another BJP-ruled state, it has won the by-polls in Dhemaji.
The Congress, which is ruling Karnataka, has won Nanjangud and leading in Gundlupet - the two seats it held.