His hearing comes one day after the sentencing of 45 pro-democracy campaigners - part of a group known as the Hong Kong 47.
Sporting a brown jacket and glasses, Lai smiled and waved to his family and the public as he entered the courtroom, looking in good spirits, though he appeared to have lost weight since his arrest several years ago.
Outside the court, dozens of people waited in line to show their support for the media mogul.
A similar crowd had gathered on Tuesday for the sentencing of the Hong Kong 47, which included some of the biggest names in Hong Kong’s pro-democracy movement, like Benny Tai and Joshua Wong.
When asked if he had tried to influence foreign policy on Hong Kong through his list of overseas contacts - which include the likes of former Taiwan president Tsai and high level US officials - Lai replied "never".
Asked about his meeting with then US Vice President Mike Pence, Lai said he did not ask anything of him.
"I would just relay to him what happened in Hong Kong when he asked me," he told the court.
He was also asked about his meeting with then secretary of state Mike Pompeo, to which he said he had asked Pompeo: "Not to do something but to say something, To voice support for Hong Kong."
Lai is one of hundreds of activists, lawmakers and protesters that have been detained under the NSL, which Beijing claims was necessary to quell the unrest in Hong Kong that emerged in 2019.
In its daily press briefing on Wednesday, China's foreign ministry spokesman Lin Jian slammed Lai, calling him the "main plotter and participant of the anti-China chaos in Hong Kong".
Beijing considers Mr Lai a traitor who sought to undermine China's security. But critics say Mr Lai's case is yet another example of Beijing's tightening grip on the former British territory.