Setti Warren, the former mayor of Newton who also ran for governor in Massachusetts and the U.S. Senate, died unexpectedly at his home Sunday. He was 55 years old. A cause of death has not been released.

Warren was most recently the Director of the Institute of Politics at Harvard's Kennedy School.

"Setti was a beloved member of our community, and we're devastated by this heartbreaking news," the school said in a statement.

Warren, a Democrat, was the Mayor of Newton from 2010 to 2018. He was the first African American to be elected mayor in Massachusetts.

Warren made a brief, unsuccessful run for governor in 2017. He also ran for the U.S. Senate in 2011, in a race later won by Elizabeth Warren.

Warren was also an Iraq War veteran and a former Naval Intelligence Specialist. He had previously worked in the White House under former President Bill Clinton and was on former Sen. John Kerry's staff.

"As a veteran, mayor, and mentor, Setti Warren spent his life to serving others and inspiring young leaders. Above all, he cherished his family and his role as husband and father," Massachusetts Gov. Maura Healey said in a statement.

"I had the privilege of working alongside him and he did this work for all the right reasons. I will miss his smarts, energy, compassion, and most of all, his heart. My thoughts are with his family and loved ones, the Harvard community, and all who knew him."

"Setti was charismatic. His smile lit up a room. He drew people to him and turned their energy into positive action. It makes total sense both that he was Class President at Newton North for four years and Student President at Boston College," current Newton Mayor Ruthanne Fuller said in a statement.

Warren leaves behind his wife Tassy and two children, Abigail and John.