The first step to being fondly missed is to leave.

Leonard Slatkin had his share of critics when he ended his term as music director of the National Symphony Orchestra in 2008, but his subsequent visits have been mostly affectionate reunions. Thursday’s NSO concert at the Kennedy Center continued the pattern, with applause and even a few cheers before Slatkin had given a single downbeat or characteristic spoken introduction.

The occasion was Slatkin’s 75th birthday, Slatkin giving himself the present of a program playing to his strengths and enthusiasms: accessible novelty, Romantic-era grandeur and American symphonic ambition. (The program repeats on Saturday.)

The new music was a curiosity: “Yet Another Set of Variations (on a Theme of Paganini),” a collaborative work Slatkin originally conceived in the ’90s, collecting glosses on Paganini’s familiar 24th violin caprice by a quintet of composers, with Slatkin himself providing the finale. For Slatkin’s birthday, five more composers were commissioned, including former NSO bassoonist Truman Harris, as well as Slatkin’s wife, Cindy McTee, and his son, Daniel.

In general, the older charms had more arresting atmosphere, especially Donald Erb’s swoops and shudders and Claude Baker’s buzzy haze. Newer contributions were more pastiche-like, though not without skill — Daniel Slatkin’s catalogue of 21st-century movie-soundtrack cliches was wittily spot-on. Most ingenious was John Corigliano, recombining the theme’s DNA into a chorus of “Happy Birthday.” The playing was a bit ragged (more than one entrance stuttered), but colors and effects were vivid.

Soloist Olga Kern took the stage for Sergei Rachmaninoff’s First Piano Concerto, a youthful gantlet of virtuosity. Kern is a pianist of muscle and blazing, headlong speed: the densest passagework cruised, even occasionally hurtling past Slatkin’s warm, firmly outlined accompaniment. Still, the performance was diffuse, a collection of often thrilling and lovely episodes that nevertheless remained episodic. (Slatkin egged the audience into demanding an encore: Sergei Prokofiev’s diabolically rollicking Étude, Op. 2, No. 4, Kern in high gear the whole way.)

More satisfying was Aaron Copland’s Symphony No. 3, a perennial front-runner for the Great American Symphony. It’s a Slatkin specialty, the work he chose for his 2008 farewell. The orchestra hadn’t performed it since then — symbolic, perhaps, of how Slatkin’s goal of reorienting the NSO around American repertoire never really took hold. But it was good to have it back, in a bold and confident interpretation featuring some of the evening’s best playing.

Having opened the concert jokingly referencing current political enmity, Slatkin closed in earnest accord with Copland’s optimistic, egalitarian national vision. The subsequent ovation (and another round of “Happy Birthday”) lauded Slatkin’s return, but also, one hopes, his buoyant steadfastness.