LAWYER PROFILE
Mark Leddy

Mark Leddy

Global 2026

Chambers ranking badge
Share profile
Chambers ranking badge
Cleary Gottlieb Steen & Hamilton LLP
 Cleary Gottlieb Steen & Hamilton LLP

Ranked in 1 practice area

Competition/Antitrust

USA

14 years ranked

Competition/Antitrust

USA

14 years ranked

About

Provided by Cleary Gottlieb Steen & Hamilton LLP

Practice Areas

US and European antitrust law, including civil and criminal litigation, analysis of competitive issues in mergers and acquisitions, and appearances before antitrust regulatory agencies and the U.S. federal courts.

Career

Joined firm as partner, 1986. Resident in firm’s Brussels office (1991-94). US Department of Justice (1972-86); Deputy Assistant Attorney General (1984-86). JD, Boston College Law School (1971); BA, Boston College (1968).

Professional Memberships

Massachusetts and DC Bars; U.S. Supreme Court and various circuit courts of appeal.

Chambers Review

Provided by Chambers

Chambers Global Guide

Competition/Antitrust - USA

Foreign expert in Belgium
Individual Editorial
Mark Leddy is commended for his representation of a broad array of prominent clients in competition disputes. His previous DOJ experience bolsters his ability to handle cartel investigations.Mark Leddy is commended for his representation of a broad array of prominent clients in competition disputes. His previous DOJ experience bolsters his ability to handle cartel investigations.
View foreign expertise table

Ranked Individuals at Cleary Gottlieb Steen & Hamilton LLP (176)

Africa-wide

Belgium

Brazil

  • Profile image of Francisco L Cestero
    Francisco L Cestero

    Banking & Finance (International Firms)

    View profile
  • Profile image of Richard J Cooper
    Richard J Cooper

    Banking & Finance (International Firms)

    View profile

What success is built on

Chambers is the leading data and intelligence partner for the legal sector.

Explore thought leadership