Last night, the third and final season of HBO’s “The Leftovers” opened with Doomsday pilgrims eagerly awaiting the Rapture, circa 1844. As the days of reckoning passed by without a peep, a cover of “I Wish We’d All Been Ready”—originally by the contentious father of Christian rock himself, Larry Norman—began to play. Such a meta musical choice perhaps would raise an eyebrow without any context. But “The Leftovers” and its showrunner Damon Lindelof (of “Lost” notoriety) consistently have used music as part of the show’s ongoing conversation about society’s reconfiguration following the disappearance of 140 million people worldwide. Sometimes that means a Groundhog Day-like loop set to the Bellamy Brothers’ “Let Your Love Flow” as Rev. Matthew Jamison cares for his catatonic wife; other times it’s as on-the-nose as Grandmaster Melle Mel and the Furious Five’s “White Lines” kicking in as Liv Tyler’s character snorts coke.

At the helm of these winking choices is music supervisor Liza Richardson, whose highlight reel includes music-heavy TV shows like “Friday Night Lights,” “Parenthood,” and “Narcos.” But for nearly a decade before starting to soundtrack TV’s airwaves, Richardson became well known on the radio dial as a DJ with Los Angeles’ influential NPR affiliate KCRW. It’s a position she holds to this day, 25 years later, with a Saturday night show playing under-the-radar indie rock, disco punk, and throwback soul. In the ’90s, Richardson began experimenting on her show by playing spoken word over instrumentals, getting Viggo Mortensen to read his own poetry and Björk to recite Georges Bataille’s Story of the Eye. From there, a more literal mash-up of narrative and backing tracks seemed spot-on, starting with music supervision duties for 2001 indie-film classic Y Tu Mamá También.

We spoke to Richardson about the oft-unseen nuts and bolts of music supervision, as well as what to expect for the music of “The Leftovers” season three.

Pitchfork: Take us through a standard timeline, from start to finish, of music supervision on a TV episode.

Liza Richardson: First I read the script and make a breakdown of the life of the episode. I use it as a communication tool with my staff, producers, and studio or network that I’m delivering to. It contains every spot in the episode that would contain music, like scenes in restaurants or even in an elevator. There’s always muzak in an elevator in every TV show. But in real life? Almost never.