[6] He moved from Massachusetts to Baltimore to attend Goucher College,[7] where he served as the president of the student government association and graduated with a Bachelor of Arts degree in political science in 2008.

[3] During his tenure, Cohen gained a reputation as a progressive, an ally to Baltimore Mayor Brandon Scott,[8][15] and as one of the most effective members of the city council.

[30] During his 2016 city council campaign, Cohen criticized Mayor Martin O'Malley's CitiStat and zero-tolerance crime policies as "failures".

[12][32] In July 2019, Cohen introduced a bill requiring agencies that interact with children and families to train employees on how to respond to trauma.

[33][34] The bill, which was later renamed after the late U.S. representative Elijah Cummings, passed, and was signed into law by Mayor Jack Young in February 2020.

[40] He also suggested using universal basic income to give squeegee workers direct payments to encourage them to stop washing car windows at intersections.

[41] During his 2024 city council president campaign, Cohen supported State's Attorney Bates' increased use of the citation docket to address low-level offenses, such as drug possession and loitering.

[45][46] Cohen supported Mayor Catherine Pugh's proposal to provide free community college for high school graduates.

[51] During his 2024 city council president campaign, Cohen supported universal preschool and implementing restorative practices and conflict resolution training in schools.

[60][61] In March 2017, Cohen introduced a resolution calling on U.S. Immigration and Customs Enforcement agents to "not target anyone who merely lacks proper documentation" or students permitted to study under the Deferred Action for Childhood Arrivals program.

[62] In May 2021, he was arrested and charged with civil disobedience for participating in a CASA de Maryland protest in Washington, D.C. to pressure lawmakers to pass legislation creating a path for citizenship for immigrants.

[66] In March 2019, Cohen introduced a resolution calling on Baltimore City Public Schools to adopt a policy protecting transgender students against gender discrimination.

[68][69] In May 2022, following the leak of a draft opinion in the U.S. Supreme Court case Dobbs v. Jackson Women's Health Organization, which would overturn Roe v. Wade and Planned Parenthood v. Casey, Cohen introduced a resolution calling for the creation of a city fund to support reproductive health care service providers, which was approved by the Baltimore City Council.

[73] In June 2023, Cohen introduced an amendment to the city budget to move $1 million in funding from the Baltimore Office of Promotion & the Arts to the city's public library system to assist with implementing the Peer Navigators program, which helps connect community members with addiction and behavioral health issues with experts.