A native of Villabate, Alaimo studied at the Palermo Conservatory and then the L'Accademia di La Scala in Milan before making his début in 1977 at the Teatro Fraschini in Pavia as the title hero in Gaetano Donizetti's Don Pasquale.
In 1980 he made his first appearance at the Piccola Scala in a production of Carlo Evasio Soliva's La testa di bronzo and performed for the first time at the Maggio Musicale Fiorentino as Radamanto in Giulio Caccini's Euridice.
He sang the role of Mustafà in Gioachino Rossini's L'italiana in Algeri for his United States debut at the Lyric Opera of Chicago in 1987.
In 2011, he appeared at Teatro Massimo Bellini, in Il Barbiere Di Siviglia, and Le Convenienze Ed Inconvenienze Teatrali.
[1] His nephew, Nicola Alaimo, is a successful baritone, born in 1978, who has worked with Riccardo Muti, among other conductors.