He attended East Lyme High School[2] and was educated at Western Connecticut State University, where he played lacrosse and studied social work.

[5] Bernstein began his career at United Way,[6] before working in senior positions at the American Israel Public Affairs Committee (AIPAC) and The David Project Center for Jewish Leadership.

[7][8] He started as the Executive Director and sat on the Israel-based senior management team for American Friends of Migdal Ohr in 2011, one of the largest NGOs in Israel.

[10] Shortly after joining ADL, Bernstein spoke about the dangers of hate groups in the US, following the Overland Park Jewish Community Center shooting.

[21][22] In 2018, online vandalism to Mapbox's naming of Manhattan led many sites such as Snapchat and the Financial Times to display antisemitic maps on their website.

[32] Following the incidents, he criticized New York City Mayor Bill de Blasio for describing antisemitism as a "right-wing movement" instead of offering a "long-term solution.

Prior to the pandemic reaching the U.S., Bernstein spoke about how the Anti-Defamation League had uncovered early discussions about extremists planning to weaponize the virus.

"[42] In response to the January 2022 Colleyville synagogue hostage crisis, Bernstein said, "There's been more and more investment in security in the different major cities and communities around the country but it needs to stay that way.