The coalition was headed by Prime Minister Najib Razak, whose popularity plummeted after $1 billion went missing from a state-owned investment fund.
Former Malaysian Prime Minister Mahathir Mohamad on Thursday bagged a shocking election victory at the age of 92.
In an eight-minute speech made at the press conference, he indicated the King will decide who will be the country's next Prime Minster as no single party has the majority.
Mr Mahathir was also a mentor to Mr Najib, who became prime minister in 2008.
Asked on Thursday if Najib would be prosecuted, Mahathir said: "If anybody breaks the law, and that includes a journalist, they will be brought before the court".
Ultimately the explosive allegations of corruption, coupled with anger at rising living costs, proved too much for Malaysia's 15 million voters, already sick of racially divisive politics in the multi-ethnic country and graft scandals under years of BN rule.
If Mahathir's coalition takes over the government, investors have to grapple with the impact of the PH's pledges to abolish the goods and services tax, restore a petrol subsidy, increase minimum wages and review infrastructure projects.
Mahathir said after declaring victory overnight that the king would sign his letter of appointment on Thursday.
He said he would be sworn in Thursday. "Regardless of the result, which party won, this proves the Malaysians' voice are heard through fair and clean election", Wong said.
The US has nothing on Malaysia when it comes to gerrymandering.
The win for the opposition ended the reign of Najib Razak, a former protégé of Mahathir, with whom he fell out after a scandal involving the state development fund 1MDB broke out.
Najib has rejected the accusations and his attorney general has cleared him of any wrongdoing.
As the former head of Barisan Nasional, Mahathir served 22 years as the country's leader before retiring in 2003.
For the first time in 60 years, Malaysia's ruling coalition has been voted out of power and the tale is nothing less than dramatic.
It is unclear what was discussed between Datuk Seri Wan Azizah and the Agong, but with PH planning to free her husband and iconic opposition figure Anwar Ibrahim from a controversial sodomy conviction to become prime minister, Sultan Muhammad V's pardon will be required. Cars honked their horns as they sped past.
Following the 2006 visit, PTI chief Imran Khan in an interview to The Guardian in 2012, stated that Mahathir Mohamad is one of the few global leaders whom he has always admired.
Bridget Welsh, a Southeast Asia expert at John Cabot University in Rome, said it was hugely ironic that Mahathir, who damaged Malaysia's democratic institutions with his strong-arm rule, has returned as its political savior.
Sustaining that kind of momentum will not be an easy task, particularly as the opposition transitions from campaigning to governing - with Mahathir claiming he will eventually step aside - and supporters of the defeated ruling coalition begin realigning post-Najib using their deep patronage networks and other levers of influence.
The added period of uncertainty had the effect of feeding into rumors that BN may not accept an opposition win and that raising concerns about the outbreak of violence.