Trumpeter and composer Wadada Leo Smith. (Scott Groller/Scott Groller)

Wadada Leo Smith’s music is among the most abstruse, demanding jazz out there. And organizing it into a four-hour, 19-part work like 2012’s “Ten Freedom Summers” doesn’t ease the effort. Hence, one doesn’t expect to go into a performance even of excerpts from that work and be deeply moved — but, at least on Wednesday night at Georgetown Day School, one would be wrong.

Trumpeter-composer Smith’s concert was a keynote of GDS’s Social Justice Days, and it followed a talk by Washington Post reporter Wesley Lowery on the lessons he learned reporting out of Ferguson, Mo., in 2014. Perhaps it was this context that brought emotional impact to Smith’s music. Perhaps, too, it was the extraordinary musicians assembled for the night: a nonet featuring two tenor saxophonists (Brad Linde, a GDS teacher who organized the concert, and Patrick Booth), second trumpeter Ryan Frazier, guitarist Aaron Quinn, cellist Janel Leppin, pianist Erika Dohi, bassist Luke Stewart and drummer Jonathan Taylor. Individually and collectively, they played magnificently.

But the power of Smith’s own expressiveness can’t be dismissed. The opening “Dred Scott: 1857” began with a maelstrom of cymbals, guitar, cello and bass (pianist Dohi was also playing, but inaudibly); the horns then entered, hard to distinguish in the whirlwind. But Smith stopped them all short with a series of piercing, painful shrieks. He went on, playing anguish on his horn with almost supernatural directness (amplified by the band’s silence).

The catharsis continued. “Rosa Parks and the Montgomery Bus Boycott, 381 Days” found the ensemble droning softly in one key, Smith playing gorgeous figures in another. The piece was somber, but also an unmistakable call to arms. The sidemen shared in Smith’s passion, though perhaps none more than Stewart, whose look of concentration as he bowed the bass was complemented by a physical intensity that shook the wool hat on his head.

“Democracy,” which began with the first true cacophony of the evening (Smith later explained that it was a metaphor for democracy: “a scattered dialogue about nothing”), gave way to the mad fingering and strong, unbending tone of Frazier’s trumpet; the leader’s trumpet would present the climax with a coarse, unaccompanied groan. The finale, “Malik Al Shabazz and the People of the Shahada,” was mainly a feature for Linde, who — before he was capped by a stunning diminuendo from Dohi — elevated his sax slowly from its lowest range to its highest, and, not coincidentally, from sorrow to hope.

Speaking to the audience afterward (in keeping with the social justice theme), Smith emphasized the opening “Dred Scott” as “representing the first debate about race in our country. He opened up multiple cans of worms that are still happening today . . . we should do something about it.

“I think we should wake up.”