John Michael Katko (born November 9, 1962, in Endwell, New York) is an American attorney and former Republican U.S. Congressman who represented New York's 24th congressional district from 2015 to 2023. Raised in Camillus, New York, he earned a Bachelor of Arts from Niagara University in 1984 and a Juris Doctor from Syracuse University College of Law in 1987. Before entering politics, Katko had a distinguished career as an Assistant United States Attorney in the Northern District of New York, where he led the organized crime division in Syracuse and prosecuted numerous cases under the RICO Act, earning recognition for combating organized crime and public corruption.

As a moderate Republican, Katko served on key committees including Homeland Security (where he became Ranking Member), Transportation and Infrastructure, and Ethics. He co-chaired the Cyberspace Solarium Commission, focusing on cybersecurity and national security issues. Known for his bipartisan approach, he supported measures like the Bipartisan Infrastructure Law and voted to impeach President Donald Trump following the January 6, 2021, Capitol attack.

Since leaving Congress in 2023, Katko has transitioned to the private sector as a partner at the law firm Cassidy Levy Kent, leveraging his expertise in cybersecurity and national security. His career has faced controversies, including allegations of insider trading scrutiny in 2020 related to COVID-19 pandemic stock trades, which he denied. Katko remains influential in discussions on cybersecurity policy and Republican moderation.