On Wednesday he attended an Independence Day military parade in Beirut, alongside President Michel Aoun. After laying wreaths at the monument for the war dead, there was a 21-gun salute.
The two, along with other Lebanese officials, are expected to attend a reception at the Presidential Palace after the parade.
His arrival Tuesday night was met by members of the country's security forces and shown live on Lebanese television. Hariri traveled to his residence in the capital after visiting the grave of his slain father, former Prime Minister Rafik Hariri.
Hariri stunned the Lebanese people when he announced on November 4 during a trip to Saudi Arabia that he was resigning from his post because he feared his life was in danger. The claim fell flat in Lebanon, where speculation swirled that he was being held hostage.
His resignation announcement plunged Lebanon into a political crisis, stoking fears of conflict between the Saudi-backed government faction and Hezbollah, a powerful Iran-backed Shia militant group whose political wing is the most powerful bloc in Lebanon's fractured coalition government.
The day after his resignation, Hassan Nasrallah, the head of Hezbollah, the Iranian-backed faction that shares power in Lebanon, suggested that Hariri was not a free man,
and that his statement had been dictated by Riyadh.
Saudi Arabia had strongly backed both Saad Hariri and his father Rafik in its bid to grow its influence in Lebanon to try to counter Hezbollah's expanding authority.
Lebanese President Michel Aoun concurred with Nasrallah, declaring that Hariri was a "captive" in Saudi Arabia.
A television interview on November 12 further fueled speculation. Hariri, appearing tired, said he would return to Lebanon "in two or three days," but that didn't come to pass.
It didn't help that Hariri did not return to Lebanon sooner, instead traveling to Gulf states and taking meetings with French officials in Riyadh.
The Lebanese, bristling at the perceived interference of Saudi Arabia, came together in a rare show of solidarity for their missing PM
, with posters of Hariri appearing across Beirut.
Hariri visited Cairo and Cyprus on Tuesday before flying to Beirut.
Shortly after Hariri resigned, Saudi Minister for Gulf Affairs Thamer al-Sabhan warned the Lebanese that they have to choose "either peace, or to live within the political fold of Hezbollah."
In his speech in the Saudi capital, Hariri said the atmosphere in Lebanon was similar to the one that existed 12 years ago, right before the assassination of his father.
"I sense what is being woven in secret to target my life," he said.
Rafik Hariri was assassinated in February 2005 when a bomb struck his motorcade near the Beirut seafront.
Lebanon is a small, resource-poor country that has long depended on oil-rich countries like Saudi Arabia for jobs and business opportunities. Hundreds of thousands of Lebanese work in the Gulf, sending back billions of dollars a year in remittances that help keep the economy afloat.