His classical compositions have been performed by orchestras, chamber ensembles, and soloists around the world, in such venues as Carnegie Hall, the Kennedy Center, and the Rose Bowl.

His professional career began at age 11, when he became the weekend pianist at the newly built La Mirada Mall – for which he credits his eclectic musical identity, being fluent in pop, rock, jazz, Broadway, and classical styles.

In 1988, Gasser received a Bachelor's degree in music from California State University, Northridge, where he studied composition with Aurelio de la Vega, and piano with Charles Fierro.

Gasser designed for the site a proprietary database to properly categorize and display classical recordings, and runs the editorial operation – including conducting interviews with classical artists and composers such as Renée Fleming, Hilary Hahn, Alan Gilbert, Hélène Grimaud, Vladimir Ashkenazy, Jeremy Denk, Daniel Hope, David Lang, Eric Whitacre, and John Corigliano.

Gasser's shift in focus to musicology, beginning in 1991, led to an extended disruption in his compositional output, with only a handful of works written before his graduation from Stanford in 2001.

[9] Gasser's most ambitious composition project in recent years has been a pair of works written in conjunction with NASA's Fermi Gamma-Ray Space Telescope (formerly GLAST) – launched June 8, 2008.

Gasser wrote the opening movement of the choral song cycle Tyler's Suite, about the tragic story of Tyler Clementi (with other movements by Stephen Schwartz, John Corigliano, and Jake Heggie, among others), which was premiered in March 2014 by the San Francisco Gay Men's Chorus at Davies Symphony Hall in San Francisco, and which will be performed subsequently in Los Angeles, Dallas, and New York.

His song cycle Repast: An Oratorio, about the life and career of civil rights figure Booker Wright, with text by Kevin Young, will be premiered on October 26, 2014, by bass-baritone Justin Hopkins at the Southern Foodways Alliance Symposium in Oxford, Mississippi Gasser's book, Why You Like It: The Science and Culture of Musical Taste (Macmillan Publishing) was released on April 30, 2019.