Many of jazz’s most innovative artists have ventured away from a traditional jazz sound in the process of forming a new creative direction. Medeski Martin and Wood, John Scofield and Béla Fleck are just a few of jazz’s modern masters — and none of them earned a reputation for originality by emulating the sounds of the past.

This is not a new thing — Charlie Parker and Dizzy Gillespie made waves with bebop because it wasn’t swing. Miles Davis got famous with Birth of the Cool, his 1949 anti-bop masterpiece, and again in 1959 with an album that didn’t have chord changes, Kind of Blue. So it shouldn’t surprise anyone that the sound of jazz is changing as it is progressing.

High-quality traditional jazz is still being created today — look at Wynton Marsalis or Harry Connick Jr. for evidence of this — but in most cases, music that sticks to old-fashioned notions of instrumentation and arrangement fails to do anything new.

One refreshing counterexample to this pattern is Brad Mehldau, a pianist who, until recently, sounded like jazz is “supposed to sound” while honestly pushing forward into unfamiliar territories of melody and material.

A couple of Radiohead covers aside, he was every jazz traditionalist’s dream come true — a Bill Evans sound-alike who played airy, virtuosic renditions of standards like “All The Things You Are” alongside pseudo-classical original works.

But like the Young Lions I discussed a month ago, it was only a matter of time before Mehldau did something to change the path of prescribed history.

By 1999, with three Art of the Trio installments behind him, Mehldau began to define jazz as “taking leads from pop music of its day, and reanimating the stylistic garment into something transfigured by the force of its composition and improvisation.”

That year, Mehldau released Art of the Trio 3: Songs, and proved to the world that he took his own words seriously. Here, sandwiched between a Hart and Rodgers classic, “Bewitched, Bothered and Bewildered,” and a light-hearted original, “At A Loss,” Mehldau not only took a lead from pop music, but grabbed a whole chunk and fit it seamlessly into a personal masterpiece.

Radiohead’s “Exit Music (For A Film)” is haunting as it appears in its original form on OK Computer, but the sparseness of the piano trio format and Mehldau’s lyrical imagination heighten the tune’s emotional power.

Beautifully sad, Mehldau’s rendition of “Exit Music” forms an important connection between the artist’s relatively traditional jazz and the popular music that jazz must continually reference in order to grow. No musician exists in a vacuum, and since musicians play the music that makes up a genre, no genre exists in a vacuum.

Each of Mehldau’s albums is brilliant, from 1995’s Introducing Brad Mehldau through 2000’s theme album, Places. But each of them follows roughly the same formula. With the exception of Places, where Mehldau composed an original piece echoing the feeling and experiences of 11 different places, each album has been a mish-mash of obligatory standard repertoire and original work.

The result is often a beautiful, consistent collection of works — some albums up, some down; some live, some in the studio — that are all creative, but unfortunately all very similar.

In 2002, Mehldau extended his embrace of popular music by teaming up with producer Jon Brion to record Largo (Brion has worked with Fiona Apple, Badly Drawn Boy, the Wallflowers and Elliot Smith, among others).

Introducing hip-hop beats, electronic sounds and guitars to Mehldau’s usually staid instrumentation, Brion helped the pianist to more fully connect with pop music, creating an album that is altogether different from his previous works. It’s busier, funkier, more frantic at times, harder, more complex — but definitely still jazz.

And in some ways, this jazz is more like the traditional jazz on which modern music was built — it’s improvisational, musically progressive and unlike most of Mehldau’s earlier work, drawing heavily from popular music in both style and instrumentation.

Brad Mehldau demonstrates that talent and creativity, and the ability to create true jazz music that upholds the principles defining the genre for over half a century, transcend all boundaries of sound and style. While other jazz modern masters have spent their entire careers creating jazz that constantly draws from other genres, Mehldau spent much of his time demonstrating that a traditional sound needn’t restrict creativity, nor must a true jazz musician stick to a traditional sound.

Throughout his career — from the gentle, delicate trio that has largely defined his sound to the disjointed, funky elements from which Largo was constructed — Mehldau has shown that it is not what you sound like that defines what you are. That is a lesson any musician can take to heart.

John Zeratsky’s “Jazz Activist” runs every other Tuesday in the Badger Herald. This is part 6. Read the entire series, plus other writings by John, at www.johnzeratsky.com.