Jacob Daniel Auchincloss (/ˈɔːkɪnklɒs/ AW-kin-kloss; born January 29, 1988)[1] is an American politician and businessman serving as the U.S. representative for Massachusetts's 4th congressional district since 2021.

His father, who is a surgeon, briefly served as acting director of National Institute of Allergy and Infectious Diseases (NIAID), after Anthony Fauci resigned.

Auchincloss's maternal grandfather, Melvin J. Glimcher, was a physician who pioneered the development of artificial limbs and the robotic arm, and was inducted into the National Academy of Sciences.

[11][12] After graduating from Harvard College, Auchincloss joined the United States Marine Corps, earning his commission through Officer Candidates School in Quantico, Virginia.

In Panama, his team of reconnaissance Marines partnered with Colombian special operations to train the Panamanian Public Forces in drug-interdiction tactics.

[14] After returning home from the military, Auchincloss ran for Newton city council on a platform of full-day kindergarten and expanded pre-K offerings.

[19] In office, he supported progressive immigration and housing policies, sustainable transportation and co-docketed the successful Sanctuary city ordinance.

[21] On October 2, 2019, Auchincloss announced his candidacy for the open Massachusetts's 4th congressional district to succeed Joe Kennedy III, who unsuccessfully ran for the Senate against incumbent Democrat Ed Markey.

On January 21, he voted to approve the congressional waiver for General Lloyd Austin, President Joe Biden's nominee for Secretary of Defense.

On June 16, 2022, seven people affiliated with The Late Show with Stephen Colbert, including Robert Smigel, were arrested by U.S. Capitol Police and charged with unlawful entry into the complex.

[36] According to a letter from Jim Jordan and Rodney Davis, the Colbert crew was let back into the building with the help of Auchincloss and Adam Schiff, leading to the unlawful entry charges.

[37] In a statement released by an Auchincloss spokesperson, Matt Corridoni said of the incident, "We do not condone any inappropriate activity and cannot speak to anything that occurred after hours.