After he graduated from Boston University in 2005, Weinstein went to India to document the life of Sharad Kumar Dixit in the film Flying On One Engine. The Director of Film at SXSW, Janet Pierson, commented that, "Flying On One Engine is teeming with life, capturing raw, intimate moments soaked through with humor and surprise... It’s clear that director Joshua Weinstein, a recent BU grad, has a great way with people as well as a great feel for the telling moment. Laughter and real warmth are everywhere." The film premiered at SXSW and IDFA in 2008. Weinstein directed the documentary, Driver's Wanted, in 2012. He was inspired to make the film because both his mother and grandfather had worked as taxi drivers in New York. It was a collaboration with acclaimed documentary editor, Jean Tsien. In The New York Times review, it was written that, "There’s an authenticity to "Drivers Wanted" that seems so true and tough that it overwhelms any standard immigrants-up-from-their-bootstraps theme." The film premiered at AFI Docs in 2012. Menashe was Weinstein’s first fiction film. The film was shot over the course of two years in Borough Park, Brooklyn, which is home to one of the largest Orthodox Jewish populations outside of Israel, a decision that Weinstein has said was motivated by a desire for authenticity. In an interview before the film's Sundance premiere, he said, "When I thought about making a film in Borough Park, in Yiddish, with real Hasidic Jews, to me, it was just as interesting as any documentary I ever made." Weinstein was nominated for Best First Feature at the Independent Spirit Awards, Breakthrough Director at the Gotham Awards, and the Special Prix du Jury at the Deauville American Film Festival.
As a cinematographer
Weinstein has worked with independent filmmakers as a cinematographer on various films. In 2011, he worked on the documentary, Give Up Tomorrow which was nominated for an Emmy and won an Audience Award and a Jury Award at Tribeca in 2011. He worked on the documentary Code of the West which premiered in SXSW in 2012. And in 2013, on which premiered at Tribeca and was released by IFC Films. He also worked on the feature film, Bikini Moon in 2017 which was directed by Oscar-nominated Macedonian filmmaker Milcho Manchevski.