Humor is a big part of Jewish life and I think it's deeply embedded in secular Judaism as I embrace and invent it. Feiffer, a nonbeliver, was one of the inventors of the kind of Jewish humor I grew up with. The book of his that I remember was titled Sick, Sick, Sick. I'm afraid to check if this memory is accurate.
Jewish humor, Jewish jokes, laughter through tears, self-deprecation, and a general vision encompassing humor have been Jewish for centuries. In fact, I wonder when that started. New Yorkers would like to take credit – I give them Feiffer, but I deny any implication that they invented humor.