Saad Hariri returned to Beirut on Tuesday night for the first time since he resigned as Lebanon’s prime minister earlier this month.
Mr Hariri was greeted by members of the security forces as he disembarked from a jet at Beirut airport, live footage of his arrival showed.
In his surprise resignation announced from Riyadh on November 4, Mr Hariri blamed Iran for its overbearing influence on his country and said he feared an assassination attempt.
The announcement triggered accusations that Saudi Arabia had coerced him into standing down in response to the growing influence of Hizbollah in Lebanon, claims which both Mr Hariri and Saudi Arabia have denied.
Fireworks were heard in Beirut as Mr Hariri’s supporters celebrated his return. More celebrations are planned for Wednesday, when Mr Hariri is expected to attend Lebanon's independence day parade in the capital.
He will then meet with President Michel Aoun, who has said he would not accept Mr Hariri's resignation until he received it in person.
Mr Hariri arrived in Lebanon from Cyprus, after meeting with Cypriot President Nicos Anastasiades.
Earlier on Tuesday, he had visited Cairo for talks with Egyptian President Abdel Fattah El Sisi, who has sought to defuse the tensions between Saudi Arabia, Hizbollah and its Iranian patrons. After the meeting, he said he would announce his "political position" when back in Lebanon.
Mr Hariri - whose father, former prime minister Rafiq Hariri, was killed in a 2005 car bombing blamed on Hizbollah - took over last year as head of a shaky national unity government which includes the powerful Shiite movement.
His resignation was widely seen as an escalation of the battle for influence between Saudi Arabia and Iran, which back opposing sides in the conflicts in Syria and Yemen.
Riyadh on Saturday recalled its ambassador to Berlin in protest at comments by Germany's Foreign Minister Sigmar Gabriel which were interpreted as a suggestion that Mr Hariri acted under Saudi orders.
The political crisis drew mediation efforts from France, with President Emmanuel Macron inviting Mr Hariri for talks in Paris on Saturday.
The French president has also telephoned his counterparts in the US and Egypt, as well as the Saudi Crown Prince Mohammed Bin Salman and UN Secretary-General Antonio Guterres to discuss "the situation in the Middle East".
While in France, Mr Hariri vowed to return to Lebanon in time to take part in the country's independence celebrations.
Mr Aoun had welcomed Mr Hariri’s trip to Paris, expressing hope it was the "start of a solution".
"If Mr Hariri speaks from France, I would consider that he speaks freely," Mr Aoun said.
"But his resignation must be presented in Lebanon, and he will have to remain there until the formation of the new government."