A native of Plainfield, New Jersey, Stephen moved to Brooklyn to work as a community organizer after graduating from Brown University. Stephen started his career by running a Lead Safe House program and an anti-predatory lending program, both in Bushwick. The Lead Safe House program helped to relocate families of lead-poisoned children out of hazardous apartments. As director of the anti-predatory lending program, Stephen worked directly with homeowners to educate the community about the dangers of subprime mortgages. Working with local elected officials and advocacy groups, Stephen was able to galvanize the community against the unscrupulous lending practices that were decimating the neighborhood with foreclosures. In 2006, Stephen went to work for the New York State Assembly, where his non-profit experience allowed him to advocate effectively for constituents.

During his tenure in the City Council, Stephen has proven to be a leader on education and early childhood issues, increased open space, and transportation safety initiatives. Stephen has passed legislation requiring the City to notify families and teachers about PCB contamination, a first-in-the-nation ban on the use of fracking and oil drilling waste byproducts, and required reporting to ensure first responders receive life-saving CPR and AED training.