Jonathan Tucker usually plays misfits and bad guys on TV and in movies -- but he became a real-life hero this weekend ... rescuing a neighbor and her kids after a home invasion.
Sources with direct knowledge tell TMZ ... the actor -- famous from 'Kingdom,' 'Hostage,' 'The Ruins,' and other shows/films -- called 911 Sunday evening to report a suspicious man who was going around banging on doors and talking to himself in his L.A. neighborhood.
We're told after Jon got off the phone with cops, he went outside after losing sight of the guy -- and when he got out there .