“Is it a perfect depiction? Absolutely not — because they have to dramatize it,” Mr. Kassem said. “I think as far as mainstream cultural production goes, it is, so far, the single work that most accurately reflects how these predatory prosecutions go, how informants are used and pressured and how these cases get packaged.”

Reading and redlining every script became Mr. Kassem’s weekend job, and he continued to point out inaccuracies and tendencies toward what he felt were racist depictions. “He did it in a wildly entertaining fashion,” Mr. Gansa said, adding it wasn’t typical Hollywood obsequiousness, which was refreshing. “His notes were astonishing in their bluntness, in their lack of convention.”

The show’s media materials describe Reda Hashem as a “C.U.N.Y. law professor,” although the school and clinic are not mentioned by name. The dean of the Law School, Mary Lu Bilek, sent a note before the current season of “Homeland” was broadcast to faculty and students touting Mr. Kassem’s involvement and his directorship of both the Clear project and the Immigrant and Non-Citizen Rights Clinic.

Mr. Kassem said he was paid a standard fee, but declined to say how much that was.

Last week, the Clear clinic earned a settlement in its lawsuit brought with the American Civil Liberties Union against the New York Police Department for its unwarranted surveillance of Muslims. And on March 1, Mr. Kassem represented four Muslim-American citizens or green card holders who claimed that by refusing to cooperate with the government, they were put on a federal No Fly list, causing lost wages.

“This takes us one step towards establishing the law,” he said in court, “so in the future, agents will not overstep boundaries.”

Mr. Gansa said that he can hear Mr. Kassem’s cadence in Mr. Sabongui’s performance, though Mr. Sabongui, in an interview, laughed and said he did not intend to do a “biopic on Ramzi Kassem.” The two met before the season and discovered they had a bit in common, each speaking French, Arabic and English.