Giuffra served as a law clerk to Judge
Ralph Winter of the United States Court of Appeals for the Second Circuit from 1987 to 1988 and to Chief Justice
William Rehnquist of the United States Supreme Court from 1988 to 1989. He joined
Sullivan & Cromwell in 1989. In 2011, Giuffra served as the lead counsel to a group of leading financial institutions in separate actions in New York State court against MBIA challenging its 2009 restructuring, winning the appeal in the New York State Court of Appeals. In 2003 and 2004, Giuffra served as counsel to the Audit Committee of Computer Associates. He later represented Computer Associates in settling investigations by the Department of Justice and SEC. In 2014, Giuffra represented
Enbridge in obtaining a unanimous jury verdict dismissing
Energy Transfer Partners’ claims seeking more than $1 billion in damages from Enbridge based on alleged tortious interference with a pipeline project. In 2015, Giuffra represented The New York State Bankers Association, which sued in federal court to overturn New York City's Responsible Banking Act, legislation that sought to regulate the activities of banks receiving deposits from the City. Judge
Katherine Polk Failla of the
United States District Court for the Southern District of New York struck down the law. During 2015, Giuffra also represented
DISH Network and
EchoStar in obtaining the dismissal of tortious interference claims seeking billions of dollars in damages in an adversary proceeding begun in connection with LightSquared’s Chapter 11 cases. In March 2017, Giuffra obtained the dismissal with prejudice of a multibillion-dollar putative class action against
UBS by
Enron shareholders who asserted that UBS bankers knew, and failed to disclose, relevant information about the energy company's finances. Giuffra represented
Fiat Chrysler Automobiles in its litigation with the U.S. Department of Justice, Environmental Protection Agency and California Air Resources Board and class action plaintiffs over alleged violations of diesel vehicle emissions regulations. In 2019, Fiat Chrysler reached final settlements to resolve those cases. Giuffra was counsel for
Volkswagen AG in the multi-district litigation arising from government investigations into the automaker's use of defeat device software. He negotiated a $14.7 billion settlement with U.S. federal and state regulators and class action plaintiffs. He since has secured the dismissal of related cases brought by the states of Alabama, Tennessee, Minnesota, Wyoming and Missouri alleging violation of state environmental laws. Giuffra reportedly was one of the attorneys who declined to represent President
Donald Trump in special counsel
Robert Mueller's investigation of Russian efforts to interfere with the 2016 U.S. presidential election. Giuffra has represented former
Deputy National Security Advisor K. T. McFarland in connection with the Mueller investigation. He reportedly persuaded federal investigators that McFarland had not intentionally misled them about her exchanges with former
National Security Advisor Michael Flynn regarding conversations with Russian Ambassador
Sergey Kislyak concerning sanctions targeting the Russian government. In 2022, Giuffra represented
Allianz when the SEC and DOJ investigated the "Structured Alpha" funds managed by Allianz. Guiffra helped Allianz reach a settlement with a guilty plea of $6 billion in payments to investors and government authorities. Giuffra represented
Goldman Sachs in
Goldman Sachs Group, Inc. v. Arkansas Teacher Retirement System, which was a $13 billion class action lawsuit seeking damages after the 2008 financial crisis. Following 13 years of litigation, Giuffra and his team successfully reversed the decision from a lower court to end the case in favor of Goldmans Sachs in 2023. At Sullivan & Cromwell, Giuffra is currently leading the appeal against the
prosecution of Donald Trump in New York, which had produced a criminal conviction and
unconditional discharge in January 2025. In April 2025, President Donald Trump dialed Giuffra into an
Oval Office meeting with the chairman of the law firm
Paul, Weiss, which Trump had targeted as part of a larger retaliation campaign against attorneys and law firms that represented his political opponents. Giuffra helped facilitate a resolution between Paul, Weiss and the White House after both sought his involvement. ==Public service and political activities==