WASHINGTON — Jamison Ross sauntered onstage at the National Museum of Natural History here on Saturday with the solicitous gleam of a casino floor manager, his bulky frame encased in a suit and his face bearing a wide-open smile. Graciously, he initiated a round of applause for his fellow hopefuls in the 25th-annual Thelonious Monk International Jazz Competition, and another for the event’s unflappable house band. Then he sat down, picked up a pair of brushes and counted off “Bye Bye Blues,” an uncomplicated song recorded by dozens of American entertainers from the 1930s on.


Mr. Ross, 24, from Jacksonville, Fla., was the last of 12 drummers given a small window to make an impression. It had been a long afternoon — longer than usual, because of the logistics of swapping a dozen drum risers on and off the crowded stage — but he exuded good feeling.


He had a light but authoritative touch, bringing deep pull to the swish and snap of his brushes on the snare. Later, using drumsticks, he made a swinging ride cymbal pattern feel like a necessary tonic. He did nothing even approaching newness, but he seemed incredibly easy to play with. The bassist Rodney Whitaker and the pianist Geoffrey Keezer, laying into the groove with him, both perked up and uncoiled.


What is the measure of a great jazz drummer? Dynamic flexibility? Catalytic chemistry? Alertness to the moment? Mastery of form? This was all worth mulling over on Saturday and Sunday, throughout the course of this prestigious competition, which changes its instrumental focus from one year to the next. For some unknown reason the drum kit has been the focus only once before, 20 years ago.


State-of-the-art jazz drumming has changed drastically since then, becoming more about pulse and elasticity, incorporating a host of complex microstrategies from Cuban and Middle Eastern and electronic music, along with hip-hop. You wouldn’t know it by listening to Mr. Ross in the competition semifinals. But he was one of three to advance to the finals, and he took first place at the Kennedy Center here on Sunday night, winning over a panel of judges that represented excellence in his field: Jimmy Cobb, Ben Riley, Peter Erskine, Carl Allen, Terri Lyne Carrington and Brian Blade. His award came with $25,000 in music-scholarship funds and a recording contract with the Concord Music Group.


Mr. Ross’s peers on Saturday, culled from several hundred submission tapes, hailed from six states as well as Germany, Israel and Slovenia. According to competition guidelines, they were all under 30, and each had to play a solo; include one Thelonious Monk composition; incorporate brushes or mallets along with drumsticks; devote some time to ballad work; and make use of the entire house combo, which also included the saxophonist Jon Gordon, who won the Monk Competition in 1996.


A handful of competitors found room to express themselves within that framework, mostly in modest terms.


But the three finalists all presented a strong grasp of group interplay as well as a show of competence. Along with Mr. Ross, they were Justin Brown, 28, and Colin Stranahan, 26. Both played the trickily syncopated Monk tune “Evidence” but in strikingly different ways: Mr. Brown coolly demolished his version, raining single-stroke rolls around his toms and snare, while Mr. Stranahan worked more with tension and release, employing a rigid rock groove that finally shifted into swing.


Their mini-sets were about equally musical, full of polyrhythmic suggestion and graceful filigree, and it was clear that they both have high-level experience. Both of them will be working in New York this Tuesday through Sunday: Mr. Brown at the Jazz Standard, in a sextet led by the pianist Gerald Clayton, a former Monk Competition finalist himself; and Mr. Stranahan at the Village Vanguard, with Kurt Rosenwinkel’s Standards Trio.


The makeup of the finalists was a reminder, in case anyone needed it, that today’s jazz musicians come as rigorously prepared as professional athletes: Mr. Brown and Mr. Stranahan both started young, putting in shifts at the Brubeck Institute before heading to conservatories in New York; Mr. Stranahan later enrolled in the elite postgraduate program that is the Monk Institute’s other major gift to serious young musicians.


As for Mr. Ross, he figured prominently in “Chops,” a 2007 documentary about the Essentially Ellington High School Jazz Band Competition, held by Jazz at Lincoln Center. (Significantly, he and Mr. Brown both came up playing in church; you’ll find YouTube videos of each of them displaying their technical prowess, in the ecstatic recent tradition of “gospel chops.”)