Biden is expected to name a foe of Big Tech to head the Department of Justice’s antitrust division.

The White House is preparing to announce it will nominate Jonathan Kanter to be the top antitrust official at the Department of Justice, according to people familiar with the situation.

Mr. Kanter’s nomination to serve as the Justice Department’s assistant attorney general for the antitrust division could be announced as soon as this week, according to those people, who requested anonymity because the information is still confidential.

The likely nomination comes at a critical moment, as the administration is looking for ways to rein in the power of big technology firms like Facebook, Google, Amazon and Apple. Earlier this month, President Biden signed a sweeping executive order aimed at increasing competition across the economy and limiting corporate dominance.

Mr. Kanter, a longtime antitrust lawyer, has built his career largely around working for the rivals of Google, Facebook, Amazon and Apple. He is the founder of Kanter Law Group, which bills itself online as an “antitrust advocacy boutique.” He previously worked at law firm Paul, Weiss, Rifkind, Wharton & Garrison.

Mr. Biden has named other critics of Big Tech to prominent roles, such as appointing Lina Khan, a critic of Amazon, to chair the Federal Trade Commission.