For eight years, Sean Callery composed and created the heart-pounding scores for Fox’s “24” — music designed to keep audiences on the edges of their seats and drive them through Jack Bauer’s tension-filled days, often with wall-to-wall music. “We had at least a couple of episodes with 42:30 of score — it was literally every frame,” he recalls.

But things have quieted down for the West L.A.-based composer — well, sort of. Callery now scores three series: “Bones” (Fox), “Elementary” (CBS) and Showtime’s award-winning “Homeland.” Of the latter, he says, “I had the naive presumption that because there was going to be less music in ‘Homeland’ that it would be an easier composing experience. But I quickly learned there were all sorts of new challenges I had never encountered.”

While “24” scores were built with a pulsing bed of rhythmic synthesizers, for “Homeland,” Callery opted for an entirely different palette, one drawn from his days playing jazz during college. “Claire Danes’ character, Carrie Matheson, has a bipolar disorder, which gives her personality a lot of traits I find indigenous to the jazz idiom. There’s a lot of spontaneity, impulsivity, improvisation and unpredictability — all things that you’ll find at play if you go to a great jazz concert.”

The jazz-filled main title features a trumpet played over imagery of America’s recent history of dealing with terrorism. “The trumpet is sort of a mournful cry against all that imagery,” he says. “Instead of playing to the urgency and the fight and the battle, instead you’re playing almost a contrapuntal, mourning tone. It’s a crying out.”

Similarly, Callery occasionally plays small handfuls of sparsely placed solo jazz piano chords to convey Matheson’s isolation and aloneness. “There’s a melancholy, real sadness sometimes in jazz. And that’s a great way to portray Carrie’s inability to connect with the world, something she’s desperately trying to do.”

It is that kind of delicacy, he says, that posed the greatest challenge. “Those are moments you have to be careful with. It’s something I had never encountered before this show. In ‘Homeland,’ the music must never inform the audience as to how they should be feeling. The characters sometimes have some real ambiguity, and the producers prefer to hold the viewer responsible for interpreting the meanings of things. The cues have to be transparent — there’s a narrower window for the music to hit a bull’s eye. It’s kind of like using only three or four lines to draw a picture.”

On the flip side is Callery’s music for CBS’ “Elementary,” a reboot of Sherlock Holmes, which features Baroque classical motifs and orchestration. “For me, Holmes has a sense of detail, precision and elegance, and classical music has that same sense of precision.”

The composer often uses cello to point to those elements of Holmes’s character. “It’s well-mannered, like a proper Englishman, but it can also be propulsive when it’s playing with shorter bow strokes. And Holmes’ brain is constantly investigating, deducing and noticing — it works on so many levels like a moving clock. And Baroque classical instrumentation works well together to portray the way he thinks.”

Callery uses similarly light tones for “Bones,” despite the show’s graphic depictions of carcasses, bones, charred flesh and leaking bodily fluids.

“You have that, and then you have light, uplifting music on top of it, and it completely works. If you had the volume down, you’d think you were looking at some grisly crime documentary. But that’s what makes the show so fun.”