'NYPD Blue' Actor William McNamara Details Saving Neighbors' Pets

William McNamara might be an actor ... but the only acting he did this week was acting like a hero -- 'cause he saved multiple animals left behind in the Pacific Palisades wildfire.

The longtime film and TV actor joined us on "TMZ Live" Friday ... and, we had a ton of questions about his animal rescue operations this week -- kicking off when officers closed the roads into the Palisades.

McNamara explains some people left animals at home and went out for the night ... and, when they tried to come back to rescue the animals, cops wouldn't allow them in.

Billy was already in the Palisades ... so, instead of leaving, he started rescuing pets -- rounding up dogs, pigs, peacocks, horses and other animals and getting them to safety.

McNamara says he has some experience saving animals ... so, he didn't go into this with no idea what to do -- but, his eyes and lungs are messed up because of prolonged exposure to the fire.

William doesn't take any praise for his rescue efforts ... instead highlighting a few people he knows who run the Animal Advocacy Network, claiming just three of them rescued more than 300 animals since the fires broke out -- and asking the public for donations for them.

As for what to do with all the animals now, especially if their owners have nowhere to go ... listen to what Billy has to say. Clearly, it's one big collective effort.

The Palisades Fire is by far the largest of the fires currently plaguing Los Angeles ... consuming nearly 20K acres already, and it's only 8% contained at this time.

It's still early on in the recovery process ... but, regular people like Billy are already doing their best to make an impact on their community.