Born in 1919 in what was then called Petrograd, Ustvolskaya studied at the Leningrad Conservatory (as the city had been renamed in 1924). Her primary teacher was Dmitri Shostakovich, who greatly admired her ability and, according to Ross, deliberately absorbed elements of her style into his own late music. "I am a talent," the teacher told his former student, "you are a phenomenon." (He even proposed marriage to her after the death of his first wife.)

Early in her career, Ustvolskaya wrote music in the socialist-realist idiom imposed by the Soviet authorities, but she abandoned that approach by the late 1940s. (Tellingly, the composer's Wikipedia entry omits altogether the Soviet-style works from its list of her compositions.) In the 1970s she began treating explicitly Christian subject matter in her music, a risky act of resistance to Communism's atheist ideology during the repressive Brezhnev era.

Ustvolskaya's musical style — described by Ross as "austere, hieratic, an intermingling of skeletal counterpoint and crashing cluster chords" — is distinguished by extreme dynamics, tone clusters, insistent ostinato rhythms provided by piano or percussion, and repeated blocks of sound. (One Dutch critic referred to her as "the lady with the hammer.") Especially striking is her use of unusual instrumental combinations: among her works are an Octet for two oboes, four violins, timpani and piano; the Composition No. 1 (Dona nobis pacem) for piccolo, tuba and piano; the Composition No. 2 (Dies Irae) for eight double basses, piano and wooden cube; and the Composition No. 3 (Benedictus, qui venit) for four flutes, four bassoons and piano. Her Fourth Symphony — only six minutes long — is scored only for voice, piano, trumpet and tam-tam; while her Fifth (and final) Symphony calls for voice, oboe, trumpet, tuba, violin and percussion.

"There is no link whatsoever," Ustvolskaya said, "between my music and that of any other composer, living or dead."