The 61-year-old senior party leader from Uttar Pradesh takes the baton back from Nitin Gadkari whom he handed over the post in 2009.
Singh, who emerged as the consensus candidate last night after Gadkari dramatically opted out of the race for a second term, was the only candidate to file the nominations and was declared elected unopposed.
Gadkari was among the first ones to wish the new party president soon after the announcement by Election officer Thawar Chand Gehlot in the presence of top party leaders including L K Advani, Sushma Swaraj, Arun Jaitley and Venkaiah Naidu.
Gadkari, whose candidature was being pushed strongly by RSS, suddenly quit the race in the midst of allegations of impropriety by his company Purti Group.
After taking over, Rajnath Singh said, “I accept this not as a post, but as a responsibility” and said he would take the battle to a decisive end by bringing BJP to power.
He said he was taking over in not very conducive conditions in the wake of allegations levelled against the outgoing chief Nitin Gadkari.
Singh said though the party wanted Gadkari to continue as party president for a second term, but he took a moral high by deciding not to contest for a second term till his name was cleared of all charges.
The new chief exuded confidence of steering the party in the forthcoming Assembly elections in various states later this year and expressed the hope to see formation of an NDA regime led by BJP in the next general elections.
“I firmly believe that the NDA will form the government in 2014,” said Singh, adding that only BJP can tackle the country's problems and people expected it to rid the country of its troubles.
Congratulating Gadkari for frustrating the party's political opponents, BJP veteran L K Advani said, “Rajnath Singh's biggest responsibility will be to ensure that there is no compromise with any immoral act in BJP.”
He said Singh has power to bring people together and hoped the party will resolve to win lost ground in Uttar Pradesh, from where he hails.
Advani said Singh has focussed on agricultural issues and farmers and exuded confidence that he will take the party forward on these principles.
He also said the party was considered an urban party, but the results have proved otherwise. “For years we have never got success in urban areas as we have won in rural areas,” he said, citing the example of Madhya Pradesh which has seen the highest growth in agriculture sector.
Rajnath Singh earlier condemned Home Minister Sushilkumar Shinde's Hindu terror remarks, which he termed as “irresponsible” and said it indicated the party in power was not serious about its fight against terrorism.
The new BJP chief charged Congress with trying to divide the nation on communal lines and said it did only vote-bank politics.
Noting that the circumstances in which he took over to lead the party were not “conducive”, he said BJP will stand behind Gadkari in his fight to clear his name of all charges.
The new BJP chief said the country was going through troubled times and blamed the Congress for it, as it had ruled the nation for a maximum period, even as he charged the ruling party with being responsible for corruption and terrorism.
He said only the BJP can tackle the country's problems and rid the nation of its troubles and people were looking up to it for this.
In his address, Gadkari said people believe that if any party can change the future of the country, it is the BJP and hoped Rajnath Singh will take everyone together and his leadership can lead us to victory in 2014.
On his second term, he said, there has been a political conspiracy to malign him on issues he was not connected with.
Chief Ministers Nitish Kumar and Narendra Modi on Wednesday congratulated Rajnath Singh.
Narendra Modi congratulates Rajnath
Gujarat Chief Minister Narendra Modi today welcomed the certain elevation of Rajnath Singh as BJP president, saying he has always been associated with farmers which would benefit the party.
"I called up Shri Rajnath Singh ji and congratulated him. He brings with him vast experience of both organisation and administration," Modi tweeted on social networking site twitter.
"Rajnath Singhji served as Agriculture Minister in Atalji's Govt. He has always been associated with the farmers. BJP will gain from this," he said in a second tweet.