Sebastian was born and raised in Lima, Peru and came to the U.S. in 2001, right after 9/11. As an exchange student in New Hampshire, he decided to call the North Country home. Sebastian became a U.S. citizen on July 4th, 2016, and has organized rallies and community groups, such as the first March for our Lives North Country, with a focus on vulnerable communities, including the Latino community. He has collaborated with Coos County Democrats, Plymouth Area Democrats, and became the first Latino NH State Democratic delegate from the North Country, co-founded the NH Progressive Coalition, and served as Vice Chair of the NH Democratic Latino Caucus.

Sebastian joined Rights & Democracy in 2018 as a member leader and later served on the Board before becoming the NH Movement Politics Director. He was awarded the 2022 Martin Luther King Jr. Award for his activism to advance a more humane immigration system and his solidarity with the plight of the Palestinian people. Sebastian is also a 3rd year student at Harvard University Extension School, working towards an International Relations degree. In addition, Sebastian is a Leadership NH 2020 alumni. He most recently became Political Director for the NH Democratic Party.