Khan has also increasingly catered to hardline religious groups, sparking fears a win for PTI could embolden Islamist extremists.
As the Pakistan Tehreek-e-Insaf (PTI) is well ahead in the general election winning majority of the national and provincial seats, its chairman Imran Khan has promised to deliver to the common people and not resort to retaliatory measures against his political rivals.
Election officials say it will be Thursday evening local time before an official count confirms Pakistan's next government.
The fiercest part of the race is expected to be between the two right-wing parties - the Pakistan Muslim League (PML-N) of three-time Premier Nawaz Sharif, who is now in jail following a corruption verdict against him, and the Pakistan Tehreek-i-Insaf (PTI) led by former cricket star Imran Khan.
The victor will face a crumbling economy and bloodshed by militants. In the eastern city of Lahore, capital of Punjab province and the country's political heartland, PTI supporters rejoiced by waving flags and raising party slogans as results trickled in after the voting on Wednesday.
The election, in which Pakistanis voted for the national assembly, the lower house of parliament, and the four provincial assemblies, marked only the second time in Pakistan's 71-year history that one civilian government has handed power to another in the country of 200 million people.
Jeff M. Smith - from the Heritage Foundation - said it was important to acknowledge that a peaceful transition of power via a democratic election is still a rare commodity in Pakistan and thus would be a positive step forward.
In a tweet on his official account, Pakistan's military spokesman, Maj Gen Asif Ghafoor, called accusations of interference "malicious propaganda".
And Wednesday's elections are likely to alarm the two major worldwide powers most interested in the elections: the United States and China. "U hv rejected all kinds of malicious propaganda".
The military had deployed 350,000 troops at the 85,000 polling stations.
The divisive campaign is likely to complicate any coalition negotiations after the vote, if they are necessary. Another 400 were wounded.
Khan, who captained Pakistan to their World Cup cricket victory in 1992, vowed to tackle widespread corruption while building an "Islamic welfare state". Baluchistan has been hit by relentless attacks, both by the province's secessionists and Sunni militants who have killed hundreds of Shias there. Most of the revelers were young men, who danced to the sound of beating drums draped in Tehreek-e-Insaf party black and green-colored flags.
He has appealed to the youth with promises of a new Pakistan, with 65% of Pakistan's population under 30.
Polling officers count ballots at a polling station in Islamabad.
In an effort to increase voter participation, the Election Commission has declared a public holiday on Wednesday.
With 48 percent of the total vote counted, Khan's PTI was listed by the ECP in its provisional results as leading in 113 of 272 contested National Assembly constituencies.
Moeed Yusuf, associate vice-president of the Asia Centre at the Washington-based US Institute of Peace, said the top challenge for the next government will be the economic crisis.
Jemima, 44, who earlier prayed for his success praised Khan in a series of tweets, saying father of her two sons will be the next prime minister of Pakistan.
Khan has been an outspoken critic of the US -led war in neighboring Afghanistan and of USA drone strikes against militants in Pakistan.
Khan is also likely to be met with trepidation in neighbouring Afghanistan, where he has been vocal in his opposition to the US-led invasion that followed the September 11 attacks on the United States.