Soares entered dubbing in 1957, and from 1966 to 1975 he worked primarily for the dubbing studio AIC (as director and voice actor). For Brazilian television, he dubbed Oliver Hardy, Shemp Howard of the Three Stooges, Kurt Kasznar on Land of the Giants, the robot on Lost in Space, and Lloyd Gough on The Green Hornet. He dubbed Vincent Price on Batman (and in Edward Scissorhands), Slim Pickens in Dr. Strangelove, and secondary characters in the Mexican comedy series El Chavo del Ocho and El Chapulín Colorado.
Cartoon characters included Mister Magoo, Peter Potamus, Boo-Boo on The Yogi Bear Show, Mr. Peebles on The Magilla Gorilla Show, and Smedley, Gabby Gator, and others on The Woody Woodpecker Show. Soares directed the dubs of Bewitched and Punky Brewster. One of his last assignments was voicing the magic toucan in the 2001 Brazilian animated feature The Happy Cricket.