The 77-year-old - who frequently calls current US President Joe Biden “Sleepy Joe” - will be required to attend court for four days a week for the rest of the trial.
The proceedings are expected to last roughly six weeks, and will see a parade of Trump’s former aides, allies and alleged mistresses take to the witness stand against the former president.
On Monday, prosecutors argued Trump had repeatedly flouted a gag order intended to protect witnesses and jurors in the days before the trial began.
The court heard Trump, the presumptive Republican nominee ahead of November’s election, attempted to intimidate key witnesses by labelling them “sleazebags”.
Cohen credibility
Joshua Steinglass, acting for the prosecution, claimed the former president had mounted a “thinly veiled attempt to intimidate” Daniels and Michael Cohen, his former lawyer, to “keep [them] off this stand”.
At one point, the prosecution suggested he may have violated the gag order from inside the courthouse, referring to a post on Trump’s Truth Social account that branded Cohen a “serial perjurer”.
In recent days, Trump also called his former lawyer a “disgraced attorney and felon”. Cohen was sentenced to three years in prison in 2018 for tax evasion and campaign finance violations.
The credibility of Cohen may be a key factor in the case as just days before the 2016 election, Cohen made a $130,000 payment to Daniels, who claims she had a sexual encounter with Trump in 2006.
Trump allegedly reimbursed Cohen in 2017 and reported the reimbursement as legal fees.
Hope Hicks, a long-time Trump aide, is expected to testify against her former boss.
Karen McDougal, a former Playboy model with whom Trump allegedly had an affair before buying her silence, is another likely witness.
‘Assault on America’
Media helicopters followed Trump’s motor convoy as he left Trump Tower and headed for the court in lower Manhattan.
Although his mandatory court appearances mean he cannot take to the campaign trail, he used the court as a backdrop to a stump speech, claiming he was being persecuted by Biden.
The presumptive Republican nominee told reporters he was “proud to be” at the Manhattan Criminal Courthouse, before claiming Biden was using the trial as “an attack on a political opponent”. He added: “It’s an assault on America.”
He then headed in to take his seat. Photographs and sketches of Trump in court showed him flanked by his lawyers, with his brow furrowed and hands clasped on the table in front of him.
The early weeks of the trial will be devoted to selecting jurors, with Trump - despite having been synonymous with New York for decades as a real estate developer - claiming it would be impossible to receive a fair trial in the city.
Thousands of prospective jurors will answer dozens of questions before they can be whittled down to the 12 men and women who will decide whether to convict the former president.
They will be quizzed on their level of education, what social media platforms they use, and whether they have listened to Cohen’s podcast or read Trump’s books, among other considerations.
If Trump is found guilty, it could mean he serves time in prison. There is no constitutional rule barring candidates from running a campaign from behind bars.
Monday’s court proceedings mean Trump is the only US president to have stood trial on criminal counts.
Richard Nixon was protected from criminal prosecution following the Watergate scandal when his successor, Gerald Ford, controversially pardoned him.
A grand jury that investigated Nixon had planned to charge him with bribery, conspiracy, obstruction of justice, and obstruction of a criminal investigation. Several members of his administration stood trial and were convicted.
