By Siddhartha Mitter

''Bem-vindo à musica brasileira," said singer Seu Jorge, taking the stage Wednesday at the Museum of Fine Arts. ''Welcome to Brazilian music.

He proved himself a worthy ambassador, delighting a post-collegiate, hipster crowd with 90 minutes of spare, taut songs that lurched from samba and bossa nova to bass-heavy mainstream pop.

Having vaulted into the limelight as an actor in two rather different films - ''City of God" and ''The Life Aquatic With Steve Zissou" - the 35-year-old Jorge is touring behind a well-crafted new album, ''Cru," clearly intended to be an international breakout. (Jorge is a star back home, yet Boston's large Brazilian community was barely represented at the concert.)

Jorge is tall and rangy, with a thoughtful expression shadowed by a thicket of twisty braids. His vocal range is limited, but his gravelly tone and loping pace produce an earnest and ultimately infectious appeal. His four bandmates -- all lined up onstage, with the drum kit, not Jorge, at the center -- worked an impressive array of Brazilian percussion instruments and strings, such as the tiny cavaquinho, which resembles a ukulele.

The more off-kilter the tune, the better it sounded. ''Mania de Peitão" (''Large Chested Mania," a relaxed rant against implants) and ''Tive Razão" (''I Was Right") greatly benefited from the bizarre, staccato hoots and chirps of a friction drum called the cuica. It lent the sound a Fauvist character, dense with warm colors and sharp distinctions.

Other songs lapsed into a more generic though still tropical pop feel, with stripped-down arrangements and a thick bass. Straightforward party jams such as ''Carolina" would have been better suited to a club floor than this concert's austere auditorium setting.

At one point Jorge left the stage to his percussionists, who delivered a lighthearted primer on Brazilian rhythms. They instigated dancing, to the considerable agitation of the MFA docents who struggled, somewhat comically, to subdue the room.

Jorge is a product of the favelas, Rio de Janeiro's sprawling ghettos, and his delivery of ''Eu Sou Favela" (''I Am the Favela") was a high point of the set. The quiet, spare song is a defense of favela dignity and a call for social action. Its bittersweet tone and almost tender politics offered a sense of intimacy that the show sometimes lacked, and with it a better glimpse into the artist's soul.