Police turned water cannon on hundreds of Lebanese protesters who gathered hours before MPs passed a confidence vote on the new Cabinet.
The protesters tried to block politicians from entering Parliament to vote on the new administration, which demonstrators oppose.
The violence continued throughout the day, with 39 wounded people being taken to hospital and 241 wounded people being treated on-site by the Red Cross.
As the session started about noon, Prime Minister Hassan Diab said gaining confidence required action, not just MP's votes, but he warned the country faced imminent collapse without a clear strategy.
Mr Diab said he would draw up an emergency plan before the end of the month and that the government would initiate move to protect depositors in the cash-strapped country.
He committed to reform promises made at the 2018 international donors' conference and restated Lebanon's commitment to liberate territories still occupied by Israel in the south.
The vote of confidence passed with 63 of the 84 MPs present voting in favour. Parliamentary rules state a simple majority of those present is required.
Mr Diab said he and his 19 ministers were already drawing up an emergency plan to be introduced before the end of the month.
There has been almost five months of nationwide protests and the worst economic crisis in decades.
Thousands began travelling to Beirut from across the country on Monday evening as security forces placed reinforced concrete barriers around the city centre to foil protesters.
Wissam Daou carried a red banner reading “No trust” as he joined others trying to block roads leading to Parliament.
But security troops cleared the streets to allow convoys of MPs into the heavily fortified city centre.
"We're trying to push more to deliver the message that they no longer represent the people," Mr Daou told The National.
Maha Khalaby, out of breath after running, used her body to block vehicles she believed were carrying MPs before security troops pushed her out of the way.
“I am so frustrated,” Ms Khalaby said. “There is nothing in this country.”
After being forced off the roads, protesters increased their blockade by placing large, heavy stones on the streets.
With tear gas wafting through the streets to Parliament, the Minister of Public Works and Transport, Michel Najjar, was the first to arrive for the confidence vote, on a motorcycle.
As Mr Diab arrived for the day's session, protesters attacked the car of MP Salim Saadeh, of the Syrian Socialist Nationalist Party.
Protesters used rocks to smash the windows of his heavily dented vehicle.
Mr Saadeh was taken to hospital and treated for a head injury. He later arrived at Parliament with bruising on his left eye.
Photographer Jad Ghorayeb was hit in the mouth with a rubber bullet and was being treated at Beirut’s Hotel Dieu hospital, press freedom organisation Samir Kassir Eyes said.
The session was scheduled to start at 10.30am but quorum was not reached until shortly before noon.
Neither the Future Movement parliamentary bloc nor the Progressive Socialist Party's Democratic Gathering voted to elect Mr Diab to lead the new government.
After a meeting of the Future Movement leadership on Monday, chaired by former prime minister Saad Hariri, the party said it would not be giving its backing to Mr Diab's administration.
"The government has nothing to do with the demands of the Lebanese," the bloc said.
"Its ministerial statement is made up of scraps copied from previous Cabinet statements and does not fit the current period or the financial, monetary and socio-economic crises."
Timeline: the Lebanese uprising as it unfolded
Before the vote, Lebanon's veteran Druze leader Walid Joumblatt confirmed he would vote no-confidence during the session.
Strida Geagea, wife of Lebanese Forces leader Samir Geagea, said the party's MPs would not enter the Parliament session until a quorum was secured because they did not believe in the government.
As dawn broke on Tuesday, people began gathering in the city centre waving Lebanese flags and chanting against a political elite that has ruled the country since the civil war ended in 1990.
Awad Jadi and Samer Tarabey said they were among 700 protesters who camped out overnight near the Mohammad Al Amin Mosque.
They went to the streets at 6am to begin protesting and said they also planned to block MPs from leaving after the Parliament session.
The military, with riot shields and truncheons, pushed protesters into the central Martyrs' Square area and away from the major motorways, although traffic in the capital had largely ground to a halt already.
Protesters threw rocks over the blast wall barriers blocking off the roads leading to Parliament.
Meanwhile, anti-government protesters and pro-government supporters clashed, lobbing rocks at each other in the Khandaq Al Ghamiq neighbourhood.
Tired of years of ineffectual governance, corruption and stagnating growth, thousands have taken to the streets since mid-October to demand a new type of government.
People have called for an end to the sectarian power-sharing system and for a technocratic administration that can improve the dire financial situation.
Over a month after he was appointed on December 19, Mr Diab formed a government in January and he said the administration would urgently begin to address the country’s worsening economic crisis.
Banks have restricted withdrawals amid a currency crisis as the Lebanese pound trades at up to 40 per cent above the official pegged US dollar rate of 1,507.
Unemployment, already high, has risen sharply as companies try to weather the economic crisis.
At Tuesday's protests, tear gas wafted through the streets of central Beirut as police tried to push back protesters gathering around Parliament.
Live footage on Sky News Arabia showed a female protester waving a Lebanese flag as she sat on one of the many concrete barriers being hosed down by a water cannon placed behind the barricade.
Hundreds of soldiers and police officers were assigned to a joint security plan to ensure the Parliament vote went ahead.
In November, parliamentary Speaker Nabih Berri postponed a session after protesters stopped MPs' cars reaching the city centre.