Chicago – September 1, 2026 – Winston Taylor announced today the addition of John Thornburgh, former Assistant Chief of the Department of Justice Antitrust Division’s Chicago Office as a partner in the Antitrust & Competition Practice. Bringing both government and private practice trial and merger clearance experience across the United States and Europe, John complements Winston Taylor’s strategic emphasis on high-stakes litigation and government investigations across the firm’s transatlantic platform.
John brings extensive experience with all facets of antitrust law, including litigation, internal investigations, and merger clearance. At the DOJ, John led and managed investigations and litigations across a broad range of antitrust matters, including mergers, Sherman Act Section 1 and 2 claims, and Clayton Act Section 8 issues. This included playing a leading role on several high-profile trial teams litigating both merger and monopolization cases. As an assistant chief, John also led the Chicago office’s newly established civil enforcement team focused on antitrust issues in the agriculture sector.
“I am extremely excited to join Winston Taylor’s talented antitrust team, including some former DOJ colleagues, and help build upon the great work the group is already doing,” said John. “As antitrust issues become increasingly global and multifaceted, businesses need counsel who understand the rapidly evolving domestic and cross-border enforcement environment, and the Winston Taylor antitrust platform, particularly in litigation, is renowned and provides an ideal opportunity to help clients navigate these complex competition challenges.”
Before joining the DOJ, John represented clients in major competition litigation and regulatory matters across a variety of industries, including transportation, consumer packaged goods, grocery, communications, software, semiconductors, chemicals, and pharmaceuticals.
“John brings valuable experience from his leadership within the DOJ’s Antitrust Division,” said Linda Coberly, co-chair of Winston Taylor's Litigation Department. “His perspective further enhances our ability to advise on complex matters that increasingly span multiple jurisdictions.”
“John is an exceptional antitrust litigator with experience at the forefront of some of the country’s most consequential enforcement actions,” Litigation Department Co-Chair Brett Johnson said. “His extensive background leading investigations, developing case strategy, and litigating high-profile antitrust matters will be a tremendous asset to our clients.”
“The Midwest, particularly the state of Illinois, is a critical legal venue for antitrust enforcement,” said Bill O'Neil, managing partner of Winston Taylor's Chicago office. “John's experience shaping enforcement priorities in Chicago is a considerable asset to our antitrust bench and for our clients across industries.”