Mr Saini is considered a confidant of Haryana Chief Minister Manohar Lal Khattar.
The BJP on Friday appointed Lok Sabha MP Nayab Singh Saini, belonging to Other Backward Classes (OBC), its Haryana unit president in place of Om Prakash Dhankar as the party prepares for the Lok Sabha elections next year to be followed by the state assembly polls.
A party communication said Mr Dhankar, a Jat, has been appointed a national secretary of the party.
The appointment of Mr Saini, 53, a first-time MP representing Kurukshetra in the Lok Sabha, may help the party strengthen its hold among the OBC community as the support of Jats, who are the most populous community in the state, is largely seen to be divided among the Congress, Jannayak Janta Party and the Indian National Lok Dal.
The BJP is already in alliance with the Jannayak Janta Party (JJP) whose leader Dushyant Chautala is the state's deputy chief minister.
Mr Dhankar was appointed Haryana BJP chief in July 2020 and completed his tenure in July this year.
Mr Saini, who has been campaigning in Rajasthan, is considered a confidant of Haryana Chief Minister Manohar Lal Khattar.
He was also a minister in the previous Khattar cabinet. He was a legislator when he fought the Lok Sabha polls in 2019.
In 2019, the BJP had won all the 10 Lok Sabha seats in Haryana with party candidates winning with massive margins.
Chief Minister Khattar and outgoing state unit chief Mr Dhankar congratulated Mr Saini.
"Many congratulations to Kurukshetra MP Shri Nayab Singh Saini ji on being appointed as the State President of Haryana BJP. We are confident that the organisation will benefit from his extensive political and administrative experience and the Bharatiya Janata Party will create a new history in all the upcoming elections," Mr Khattar posted on X.
Congratulations to Nayab Singh Saini for the responsibility of state president, the outgoing state unit chief Dhankar posted on X.
The chief minister also congratulated Mr Dhankar on his new responsibility as national secretary of the BJP.
"May workers across the country benefit from your organisational experience. My best wishes for a successful tenure," Mr Khattar said.
Mr Saini's appointment comes at a time the BJP and its ally JJP have remained non-committal on contesting elections jointly.
In recent months, both the JJP and the BJP have said they are preparing to contest all the 10 Lok Sabha and 90 Assembly seats and have remained non-committal on fighting the elections jointly.
In this scenario, Mr Saini has a task at hand to further strengthen his party ahead of the two crucial elections coming up in 2024.
Shortly before the BJP central leadership appointed the new state unit chief, Mr Dhankar was asked by reporters whether a change could be expected as his term as state unit chief had come to an end in July..
Replying to this, Mr Dhankar said change is a natural process in a national party like BJP and referred to recent appointments of the party's Punjab and Chandigarh unit appointments.
No one is permanent here, Mr Dhankar, who is also a former Haryana minister, said.
A BJP worker is always prepared to take up any responsibility and role given to him, he said.
This is not a family-based party. It is a national party in which change from booth unit in-charge to national president is a natural process, he said.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)