The 75-year-old has pledged to create jobs and kickstart the economy
Emmerson Mnangagwa has been sworn in as Zimbabwe's new president at the national stadium in Harare.
Mr Mnangagwa - nicknamed The Crocodile - will serve until the end of the presidential term next year.
He has hailed the start of the country’s "new and unfolding democracy" as he made his return from exile in South Africa.
Addressing supporters hours after returning to Harare, Mr Mnangagwa pledged to create jobs and kickstart the faltering Zimbabwean economy.
75-year-old said: "I pledge myself to be your servant. I appeal to all genuine patriotic Zimbabweans to come together. We work together. No-one is more important than the other - we are all Zimbabweans.
"We want to grow our economy. We want peace in our country. We want jobs, jobs, jobs in our country."
It comes just days after Robert Mugabe resigned following on from the military taking control.
There were celebrations in the chamber as Mr Mugabe's resignation letter was read out in the country's parliament.
The veteran leader said he had chosen to step down "to allow the smooth transfer of power" and had made the decision voluntarily.
Mugabe held his last Cabinet meeting on Tuesday morning - which just five ministers attended.
An ultimatum from his own Zanu-PF party to resign or face impeachment also came and went.
Mugabe ruled Zimbabwe with an iron fist since 1980.
His sacking of then-vice president Emmerson Mnangagwa put Mugabe's unpopular wife, Grace, in prime position to succeed the veteran leader.
The army promptly seized power and put Mr Mugabe under house arrest - but insisted it had not staged a coup.
He has reportedly been "assured protection" and granted immunity from prosecution following his resignation.
He has been assured he will be protected in his home country and sources close to the negotiations have said he has "no plans" to go into exile and wants to die in Zimbabwe.
The immunity is reported to have been granted as part of a deal over his resignation on Tuesday.