Jeremy Feigenbaum, New Jersey’s first solicitor general and one of the most accomplished appellate lawyers of his generation, is joining Jenner & Block as a partner and will lead the prestigious law firm’s appellate practice in its New York office.
The move gives Jenner & Block a 37-year-old legal star who has already argued three cases before the United States Supreme Court, built New Jersey’s solicitor general’s office from scratch, and spent nearly a decade handling some of the state’s most consequential litigation.
It also represents another significant investment by Jenner & Block in the next generation of New Jersey legal and government talent, and reunites Feigenbaum with Matthew Klapper, a Jenner partner and longtime mentor who served as chief of staff to U.S. Sen. Cory Booker and later to U.S. Attorney General Merrick Garland.
“Jeremy is one of the most accomplished appellate lawyers of his generation,” Jenner & Block co-managing partners Ishan Bhabha and Randy Mehrberg said. “His first-chair experience and sound judgment — sharpened by building and leading the New Jersey Solicitor General’s Office –— position him to guide clients facing their most consequential and most sensitive matters.”
Feigenbaum left state government earlier this month after six years as solicitor general. He had served under four attorneys general — Gurbir Grewal, Andrew Bruck, Matt Platkin and Jennifer Davenport — and two governors, Phil Murphy and Mikie Sherrill.
At Jenner, Feigenbaum will handle high-stakes appeals and Supreme Court litigation as well as government investigations, commercial disputes and matters involving government and public policy. He will lead the firm’s New York appellate team and also work across several of Jenner’s litigation and government-facing practices.
“Jeremy’s arrival strengthens our New York office at every level, expanding our growing presence in the market,” said Tony Barkow, managing partner of Jenner’s New York office. “He’s a versatile litigator with the judgment and range to add value across investigations, government controversies, complex commercial disputes, and appeals, in and outside the courtroom.”
The hire also puts two prominent Jersey guys with deep government experience under the same Jenner & Block roof.
Klapper joined Jenner in 2025 after serving as Garland’s chief of staff and senior counselor at the Justice Department. Before that, he spent years as Booker’s chief of staff and served as a policy advisor in Newark. At Jenner, Klapper co-chairs the firm’s Congressional Investigations and Global Crisis Management and Strategic Risk practices.
Feigenbaum and Klapper’s relationship predates their time at Jenner, and Klapper praised his former protégé’s unusual combination of appellate talent and experience navigating state and federal government.
“Jeremy has been a national leader for almost a decade in multistate litigation and state civil enforcement, helping expand the states’ role in high-impact lawsuits across the regulatory and enforcement landscape, which will make his wisdom and experience incredibly important to our work at Jenner,” Klapper said. “Jeremy’s ability to deftly navigate multistate investigations and complex litigation is exactly what clients need when they’re facing multiple exposures that may include state attorneys general, federal regulators, and Congress.”
Feigenbaum’s rise has been unusually fast.
A Teaneck native, he interned for Senate Majority Leader Loretta Weinberg and Bergen County Commissioner Tracy Zur. He attended Brown University and Harvard Law School, where he won the Sears Prize, awarded to the top two students in the second-year class. He clerked for Ninth Circuit Judge William Fletcher and then U.S. Supreme Court Justice Elena Kagan before practicing at Kirkland & Ellis.
When New Jersey created the solicitor general’s office in 2020, Feigenbaum became its first occupant and effectively built the operation, expanding it from one lawyer to a 15-attorney office that became a significant player in national appellate litigation.
His three Supreme Court arguments included PennEast Pipeline Co. v. New Jersey; New York v. New Jersey, where he secured a unanimous victory allowing New Jersey to withdraw from the Waterfront Commission of New York Harbor; and Trump v. CASA, where he represented a coalition of 23 attorneys general in litigation involving birthright citizenship and nationwide injunctions.
He also played a central role in New Jersey’s successful court fight after the Trump administration froze federal funding for the Gateway Hudson Tunnel project, along with litigation involving consumer protection, data privacy, health care, energy, gun laws and executive authority.
Former Attorney General Matt Platkin, who worked closely with Feigenbaum, called him one of the country’s elite lawyers when he announced his departure from state government.
“In a short time, Jeremy Feigenbaum has established himself as a member of the truly elite class of lawyers in this country. His skills as an attorney, oral advocate, and strategic thinker are unquestioned,” Platkin said. “He represents the best of our profession and has used his tremendous skill to take appropriate risks with his career in order to serve the public.”
Ian Gershengorn, co-chair of the firm’s Appellate and Supreme Court practice, called Feigenbaum “a superb appellate advocate who combines a proven record arguing at the highest levels with a deep understanding of how government operates.”
“That combination will make him an invaluable addition to our appellate practice, and we’re thrilled he’ll be leading our New York appellate team,” said Gershengorn, a former acting U.S. Solicitor General.
Jenner & Block, founded in 1914, has more than 500 lawyers in the United States and United Kingdom and is particularly well known for high-stakes litigation, appellate work, government investigations and public policy matters.
For Feigenbaum, the move provides a national platform for the kind of work he has spent the last decade doing for New Jersey — and a chance to help expand Jenner’s New York presence alongside lawyers with whom he has longstanding relationships.
“Jenner’s people, culture, and firm values made it the perfect fit, particularly given its growing presence in the New York market,” Feigenbaum said. “I could not be more excited to join a group already so well respected for its appellate strength, government knowledge, strategic counsel, and broader litigation star power. I’m eager to build on that real strength with my own issues-and-appeals experience and near-decade in state government leadership roles.”