Tradition decrees that the first concert of a big orchestra’s season includes a bunch of traditional crowd pleasers — often, these days, with one contemporary work to demonstrate to the local critics that you are in fact a forward-thinking citizen of the music world. Next week, the National Symphony Orchestra will open with Beethoven and Mendelssohn, Richard Strauss and Sarasate.

The Fairfax Symphony Orchestra is evidently more willing to push the envelope. On Saturday night, it began its 56th season with a program that was both crowd-pleasing and made up entirely of 20th- and 21st-century works by American composers, including one local premiere of a piece that the orchestra had co-commissioned. It was a fun, energetic program — nothing too thorny or cerebral here — and the audience seemed to enjoy it. Why can’t this kind of thing be the norm? Honest, it doesn’t bite.

Most of the music, to be sure, was familiar concert fare. The most contemporary-sounding work on the program was John Adams’s “The Chairman Dances,” adapted from “Nixon in China,” which is a frequent curtain-raiser for American orchestras. Although Christopher Zimmerman, the Fairfax orchestra’s music director, invoked the term “minimalism” in describing it, and it certainly does open with some of minimalism’s characteristic repetitions, the piece already shows a lot of the orchestral richness that has become Adams’s trademark.

The newest piece sounded in many ways the oldest. “Shadows,” by Ellen Taaffe Zwilich, is a piano concerto written for a consortium of orchestras and spearheaded by the soloist Jeffrey Biegel, and it is almost painfully eager to please with tonality, licks of jazz and repetitions of motif combining to invite the audience in and provide clear markers to guide them along the way. With its emphasis on majestic, swelling statements, it also telegraphs that it speaks the time-honored language of classical music, thank you very much. All this adds up to something pleasant but anodyne.

The second half of the program was given over to American chestnuts: Leonard Bernstein’s “Three Dance Episodes from ‘On the Town’ ” and George Gershwin’s piano concerto in F, both with a lot of freshness to offer.

Christopher Zimmerman, music director of the Fairfax Symphony Orchestra. (Fairfax Symphony Orchestra )

The only disadvantage of playing a whole program of newer work is that the music may not be familiar to the orchestra, and with an ensemble on Fairfax’s level, which only plays six or seven concert programs a season, the challenge is audible. (This is not generally as true of a larger orchestra like the Baltimore Symphony Orchestra, which is, in any case, attuned to American music; it offered the first of two consecutive all-American programs last weekend and continues with the next one Friday.) The Fairfax players made slightly heavy going of Adams, and some of the solos in the Gershwin weren’t quite up to speed. Zimmerman’s energy and good will showed to their best effect in the Bernstein, whose music has a way of invigorating American orchestras.

You could argue that it was interesting to hear this music played without the veneer of slickness such a program might have gotten at the New York Philharmonic, where an “American evening” may still bear connotations of being lightweight — which here it entirely lacked.

Any slickness emanated from the urbane Biegel, who had a tour-de-force evening playing two concertos, both with the same unflappable facility and fingerwork that flowed like oil. If the orchestra found this music hard going, Biegel made it sound absolutely easy, and if it seemed in a couple of places as if he’d gotten caught up in his own facility at the expense of the music, he generally played with a straightforward integrity that was a good fit for this group. He concluded the evening with a melting-pot encore by an American composer of Russian descent about Asia: “Rush Hour in Hong Kong,” written in the 1920s by Abram Chasins, a rapid-fire, amusing evocation of lots of bustling people.

It was a note-perfect end to a very refreshing evening that spoke well for the programming vision of Zimmerman, who just extended his Fairfax contract for another three years. Alas, this concert isn’t indicative of the rest of the season, which returns to more familiar fare: lots of Beethoven, Strauss and Tchaikovsky.