"This was a chance for us to show the writers we support them, and to show the media conglomerates that they need to take responsibility for their own decisions and not blame the writers for their layoffs," organizer Andrew Goldberg said in a statement posted on the WGA Web site.
"For writers, this was a chance to celebrate the assistants and below-the-line employees, and to recognize the sacrifices they're making in this fight."
Goldberg was laid off Nov. 7 from his job as Seth MacFarlane's assistant for the animated show "Family Guy."
Show producers, including MacFarlane, Matt Groening and Matthew Weiner, picketed alongside assistants Monday.
"It's one thing for them to back us up when they're paid to do it," said "House" creator and executive producer David Shore. "But this was thrust upon them, they're paying a price. And they could easily resent this strike, yet they continue to support us. They deserve and have my deepest gratitude and respect."