When Chris Thomas King has played Boston in the past, he hasn’t looked much different from the character he portrayed in the Coen Brothers film O Brother, Where Art Thou?, Delta bluesman Tommy Johnson. But when he took the stage at the House of Blues earlier this month, King appeared more like his fellow New Orleans resident the rapper Master P. He emerged through a cloud of stage fog wearing a doo-rag, a black T-shirt, baggy leather drawers, and high-tech Adidases as he brandished a wireless microphone and rapped "Welcome to da Jungle," a song from his new Dirty South Hip-Hop Blues (21st Century Blues) that tells of African-American culture’s trip from the Motherland to the ghetto.

For King, it wasn’t much of a transformation. The 32-year-old son of Baton Rouge juke-joint operator and swamp bluesman Tabby Thomas has always been a chameleonic performer. His albums and live shows have swooped from backwoods shuffles to Hendrixian flare-ups to acoustic fingerpicking even as his hairstyle has ricocheted from a close crop to deadlocks to a high natural and back over the years. For the blues, however, his latest transformation is an indicator of hard times and a diminishing sense of musical identity.

With the entire music industry in the ditch, the blues market — which accounts for less than two percent of overall CD sales — is in very deep trouble. Catalogues of albums from years gone by, which have long been the bread and butter of blues labels, have been squeezed out of record stores by retailers’ perceived need to sell as many copies of current hits as possible. The margins of radio play have tightened, lessening exposure for new artists, and since the death of Stevie Ray Vaughan more than a decade ago no crossover star has arisen to bring both the mainstream’s focus and young fans to the genre.

As for older listeners who came of age hearing primal electric-blues figures like Muddy Waters and his generational successor Junior Wells in clubs, the new strain of largely white rock-influenced guitar players upon whose shoulders much of the music’s future appears to rest just ain’t doing it, with very few exceptions. In order for the blues to survive as anything more than cult music, it needs to reach and speak to new listeners. A handful of progressive labels (Fat Possum and Tone-Cool) and a few artists and producers (Epitaph president and house boardsman Andy Kulkin, the guitarist Rick Holmstrom, the North Mississippi All Stars, and King) are leading the pack in this effort.

For King, it’s more a matter of the times catching up with him. He’s been playing his hybrid of blues and hip-hop for almost a decade. For a guy who grew up in his father’s juke joint and in a gritty urban environment, the mix seems entirely natural. And inasmuch as he began making albums at age 17, he’s had enough involvement with the music business to know that now is the time to strike with a blues/hip-hop CD. Hence, Dirty South Hip-Hop Blues is on his own label.

This ambitious disc is also one of the year’s better albums, full of seductive beats, sweetly singing guitar, and lyrics that probe the racial divide and affairs of the heart with equal zeal. His previous effort, last year’s The Legend of Tommy Johnson, was a crass, weak attempt to cash in on his O Brother notoriety with traditional blues. But Dirty South Hip-Hop Blues is an artistic breakthrough. On most of its 22 numbers, King weds slide dobros, backwards six-strings, loops, and programmed rhythms, playing and arranging every instrument himself. By the time it’s all over, he’s sampled Son House, name-checked the likes of Robert Lockwood and the Jim Crow combat anthem "Strange Fruit," and exchanged gunfire with a racist sheriff in his update of the Robert Johnson legend "Mississippi KKKrossroads."

On stage at the House of Blues, his band was two turntables and a sampler handled by his sidekick DJ Spin, who provided able accompaniment as King played guitars, sang, rapped, and — to an extent — preached his way through his stories of hard times. The show had some rough sonic edges. Spin made a better second banana than soloist, and King’s gear balked occasionally following a rushed soundcheck. But in the end, King stayed true to the blues’ mandate to keep it real while providing a glimmer of hope for the music’s future.