With episode 636 on Sunday, The Simpsons finally outran Gunsmoke as America's longest-running TV show, as counted by scripted episodes. It overtook it about a decade ago in terms of how many seasons it's been on TV. That said...
“Gunsmoke,” however, was an hourlong program for about half its run, while “The Simpsons” is half-hour, and so the former retains the record for most hours of television. As well, the Western series had begun on radio in 1952.
The closest other scripted prime-time series, the family drama “Lassie,” about an ingenious collie, ran on network and then in first-run syndication from 1954 to 1974, for 591 episodes.
In a welcome coda to the Apu imbroglio, Hank Azaria (who also voices other characters on the show) is planning to let a South Asian actor take over the role and help transition the character to a less stereotypical portrayal.