[7] Shapiro is married to Toni Okamoto, author of The Super Easy Vegan Slow Cooker Cookbook, Plant-Based on a Budget, Plant-Based on a Budget: Quick and Easy, and The Friendly Vegan.

He has cited the Talmud's commandment against tza'ar ba'alei chayim ("suffering of living creatures") and other Jewish principles as influences on his animal welfare advocacy.

[13][14] He taught peace studies at a public high school in Washington, D.C.[15] He was profiled in a 2003 Washington Post Style section article entitled "Animal Pragmatism: Compassion Over Killing Wants to Make the Anti-Meat Message a Little More Palatable".

Shapiro helped spearhead the campaign to end the use of the "Animal Care Certified" logo on egg cartons in the United States.

"[19] From 2005 through 2016, Shapiro led many of HSUS's efforts to protect farm animals, including serving as Vice President of the organization's Farm Animal Protection campaign, including efforts to convince retailers, food service providers, and universities to end their use of eggs from battery-caged birds, pork from gestation-stalled pigs, and to expand their vegan options.

[32] In a written statement to POLITICO, Shapiro commented, "I’ve taken responsibility for inappropriate behavior years earlier in my career, and apologized to those who may have been offended".