Jon Santiago (born April 1, 1982) is an American physician and Democratic politician who served as the Massachusetts state representative for the 9th Suffolk district from 2019 to 2023 and Massachusetts' Secretary of the Executive Office of Veterans' Services from 2023 to 2025. He ran a campaign for mayor of Boston in 2021, but withdrew from the race before the primary election.
Santiago was born in Mayagüez, Puerto Rico and raised in Boston and is of Puerto Rican descent.
Enlisted in the United States Army Reserve while a medical student, Santiago is a Major in the United States Army Reserve and has been deployed overseas twice. He previously served as a volunteer community health specialist to the Peace Corps. Santiago graduated from Yale School of Medicine. He is a member of the Massachusetts Black and Latino Legislative Caucus.
Santiago served as the Massachusetts state representative for the 9th Suffolk district from 2019 to 2023. His district mostly comprises the South End neighborhood of Boston, though it also includes parts of Boston's Roxbury, Back Bay and Fenway neighborhoods. His 2018 victory in the Democratic primary unseated the chamber's assistant majority leader Byron Rushing, who had represented the district for 35 years, starting in 1983. Santiago had at one time been a State House intern for Rushing before challenging him to his seat.
Santiago continues to serve as an attending physician in emergency medicine for the Boston Medical Center, arguing that such a job informs his legislation, especially when it comes to matters of public health like the opioid epidemic.
Santiago resigned from the legislature on March 1, 2023, after being appointed by governor Maura Healey to become Massachusetts' Secretary of the Executive Office of Veterans' Services.
On February 23, 2021, he announced his candidacy for the 2021 Boston mayoral election.
He withdrew from the race on July 13, 2021, and later endorsed Acting Mayor Kim Janey ahead of the preliminary election. Because he ended his campaign after the withdrawal deadline, he was still listed on the ballot.
Santiago was appointed by Governor Maura Healey to serve as Massachusetts' inaugural Secretary of the Executive Office of Veterans' Services, heading the Massachusetts Executive Office of Veterans' Services. The office and the secretary position were created by legislation that had been passed in 2022, and came into creation on March 1, 2023. It assumed roles previously housed within the Massachusetts Executive Office of Health and Human Services. He resigned in 2025 to resume his medical career.