Seven years ago, Mark Zuckerberg, the chief executive of Meta, testified for the first time in Congress. After a two-week boot camp by his lawyers to prep him, he answered questions in three back-to-back-to-back hearings over two days in a baptism by fire.
Mr. Zuckerberg, 40, has had even more practice since then. He has appeared before Congress eight times and testified in court at least twice, more than any of his peers at the biggest tech companies. He has defended his company, previously known as Facebook, on issues such as privacy, child safety and the spread of disinformation.
Mr. Zuckerberg on Monday again took the hot seat, this time as the marquee witness in the Federal Trade Commission’s landmark lawsuit accusing Meta of breaking antitrust law. Regulators sued the company in the U.S. District Court for the District of Columbia over its acquisitions of Instagram and WhatsApp, saying it used a “buy-or-bury strategy” to maintain a monopoly in social media.
Mr. Zuckerberg’s turn as a serial witness has become a potent symbol of Washington’s growing frustration with the power held by Silicon Valley, fueling attempts to rein in the tech industry. Under President Trump, tech chief executives have cozied up to the administration in hopes that regulators will take a softer hand, but so far his appointees have signaled continued scrutiny.
On Capitol Hill, lawmakers have railed at Mr. Zuckerberg, accusing him of lying and having personal responsibility for various societal harms. Previous tough questioning could help him during his expected seven hours of testimony defending Meta in the antitrust trial, legal experts said.
“He seems to be much more aware of the audiences he’s speaking to compared to his earlier years,” said Adam Sterling, associate dean at Stanford Law School. “Whether it’s a deposition or a lawsuit or in front of the Senate, he can actually craft the message to the recipients of it.”
Meta and the F.T.C. declined to comment.
It’s a far cry from Mr. Zuckerberg’s start in a Harvard dorm room 21 years ago. After building “The Facebook,” he dropped out of school and moved to Silicon Valley to build the social network. His successes and failures were publicly scrutinized.
In 2021, he renamed the company Meta, an effort to shed some of the company’s baggage. He has recently courted Mr. Trump, including visiting the White House this month to try to persuade the president and his aides to settle the F.T.C.’s suit.
The government scrutiny and legal challenges haven’t inflicted lasting wounds on the company. Meta’s stock price has more than doubled since Mr. Zuckerberg’s first appearance in Congress.
Mr. Zuckerberg is likely to face a more grueling time on the stand at the antitrust trial, legal experts said. Congressional hearings feature grandstanding by lawmakers, and they are limited to a few minutes each. F.T.C. lawyers plan to grill Mr. Zuckerberg for hours. They also have a trove of his emails and other communications and plan to ask him to defend the documents that they say prove his company’s ill intentions.
“A trial is a different beast since opposing counsel will be well prepared, ask better questions and stay focused on their case,” said Nu Wexler, a former policy official for Meta and a principal for Four Corners Public Affairs.
In 2017, Mr. Zuckerberg testified in Dallas in a trial over intellectual property theft claims by a video game company, ZeniMax Media. He also testified in San Jose, Calif., in 2023 during an F.T.C. trial to block Meta’s acquisition of the virtual reality company Within.
This time, the F.T.C. is asking Judge James E. Boasberg to find Meta guilty of antitrust violations, so there is “a lot more at stake,” said Katie Harbath, a former public policy director for Meta and the chief executive of Anchor Change, a consulting firm.
For the first half of Meta’s history, Mr. Zuckerberg shied away from unscripted public appearances. In 2010, he fumbled an interview at a technology conference by struggling to respond to questions about privacy as beads of sweat ran down his face.
Most of his public witness experience has come before Congress.
Mr. Zuckerberg faced an enormous backlash from Washington lawmakers after the 2016 presidential election. Reports surfaced that Facebook had given Cambridge Analytica, a political consulting firm, access to people’s social networking data without their consent.
That led to Mr. Zuckerberg’s appearance at packed hearings in Congress in April 2018. His lawyers coached him to stay calm when interrupted and to postpone answers to hard questions, according to Meta employees familiar with the briefings.
“My team will get back to you,” he said multiple times at the hearings.
The next year, Mr. Zuckerberg faced questions from the House Financial Services Committee on the security and safety of the company’s plans for a cryptocurrency called Libra.
Representative Alexandria Ocasio-Cortez, Democrat of New York, asked Mr. Zuckerberg about misinformation in political advertisements and interrupted him. He winced occasionally and at times struggled to find answers.
Representative Maxine Waters of California, the Democratic chair of the committee at the time, accused Mr. Zuckerberg of putting the company’s fortunes ahead its users.
“You’re willing to step on anyone — your competitors, women and people of color, even our democracy,” Ms. Waters said.
“I get that I’m not the ideal messenger for this right now,” Mr. Zuckerberg replied. “We certainly have work to do to build trust.”
Mr. Zuckerberg did better in his next two appearances, legal experts and former employees said, showing more polish and control of his answers. He and the chiefs of Apple, Amazon and Google were summoned in 2020 during the pandemic for a House Judiciary Committee hearing on the power of Big Tech. In 2021, joined by the chief executives of Twitter and Google, Mr. Zuckerberg spoke to a House committee about disinformation.
Last year, Senator Josh Hawley, Republican of Missouri, demanded during a child safety hearing that Mr. Zuckerberg apologize to parents who had lost their children to bullying and other harms that Facebook and Instagram were accused of fueling.
“I’m sorry for everything you have all been through,” Mr. Zuckerberg said to parents who attended. “No one should go through the things that your families have suffered.”
Mr. Hawley said it was important to hold Meta and Mr. Zuckerberg accountable.
“This was my entire goal, to force a moment of truth,” Mr. Hawley said in an interview. “But the truth is also that he keeps sailing right on ahead and will do so until there are real consequences from Congress and in the trial next week.”
