Alberto Rabagliati was born in Milan on June 27, 1906, the only child of Leandro Valentino Rabagliati, a wine merchant, and Delfina Besso, both from Casorzo in the Monferrato hills of Piedmont. After his father's death he entered a competition run by Fox Film to find a double for Rudolph Valentino, who had died the year before, and won it. In 1927 he moved to Hollywood and stayed about four years. His acting career in America never took off, although Italian Wikipedia places him in a small part in Frank Borzage's Street Angel (1928). What he brought home was an ear for jazz, swing and scat singing, and a decision to become a singer.

Back in Italy (English Wikipedia dates the move to Rome to 1931) he sang for a short time with Pippo Barzizza's Blue Star orchestra, and in 1934 he joined the Lecuona Cuban Boys, a Cuban dance band that English Wikipedia calls a jazz band. With them he had a hit with Ernesto Lecuona's "Maria la O," and he sometimes performed in blackface. Records credited to him with the band include a 1935 Pathé single issued in France and a 1936 Columbia 78 of "Blue Rumba" and "Coubanakan." The composer and conductor Giovanni D'Anzi heard him with the band and suggested an audition for the state broadcaster EIAR. He passed, and he joined the singers of the Cetra Orchestra directed by Barzizza.

The Cetra 78s of 1939 to 1943 made him one of the best-known voices on Italian radio. Several are swing numbers written by D'Anzi: "Silenzioso slow (Abbassa la tua radio)," issued with "Illusione" as Cetra IT 692 in 1940, and "Il maestro improvvisa," which Italian Wikipedia lists as a 1940 record made with the Trio Lescano. Others are the sentimental songs that sold best: "Ba-ba-baciami piccina," "Ma l'amore no," "Mattinata fiorentina" and "C'è una casetta piccina." In 1941 he was given a weekly radio program, Canta Rabagliati, broadcast on Monday evenings, and other songwriters began working his name into their lyrics. Italian Wikipedia says his 78s together sold 100,000 copies, a large number for the period, and that he was paid 1,000 lire for a live evening.

At a time when foreign music was officially discouraged, he was allowed to keep an American-influenced style, and the Fascist government took one of his songs, "C'è una casetta piccina," known as "Sposi," as an informal anthem for its campaign to raise the birth rate. Italian Wikipedia repeats an anecdote that Mussolini personally disliked his records and once smashed one, telling him to go back to America.

His radio fame restarted his film work. From 1940 to 1965 he appeared in about twenty films, among them Carlo Ludovico Bragaglia's La vita è bella (1943), Pietro Francisci's Natale al campo 119 (1947), Joseph Mankiewicz's The Barefoot Contessa (1954) and Dino Risi's Il vedovo (1959). Italian Wikipedia adds that in 1954 Disney chose him to sing Kirk Douglas's songs in the Italian version of 20,000 Leagues Under the Sea. On stage he worked in revues and musical comedies into the mid-1950s, including Pirulì Pirulì... non andrà sempre così (1945) and Buonanotte Bettina (1963) by Garinei and Giovannini. After the war his Cetra records mixed Italian songs with French and Latin ones, such as "La vie en rose" and "La mer" (1948), "Babalù" (1947) and "Manon de Paris" with his own "Rabagliati samba" (1951). He married Maria Antonietta Tonnini in Rome on May 19, 1954, and in 1956 he recorded an album of Milanese dialect songs for Durium with the singer Evelina Sironi.

His clearest later return to the swing repertoire came on Ricordi. In 1962 the label issued Giorgio Gaslini presenta Alberto Rabagliati, an album of fourteen of his 1940s songs with the jazz pianist and composer Giorgio Gaslini credited as arranger and orchestra director. Gaslini is credited in the same way on a 1963 single of "C'è una casetta piccina (Sposi)" and "Ma l'amore no" and on the 1964 EP Quando canta Rabagliati, whose four songs include "Silenzioso slow" and "Maria la O." A full album under the title Quando canta Rabagliati followed in 1967. In June 1964 he won the television game show La fiera dei sogni, and in July he appeared with Natalino Otto and Nilla Pizzi in the special I magnifici re.

The 1970s brought a revival of 1940s music, and he sang again at the Excelsior terrace in Venice, the Piper Club in Rome and other venues. In 1973 he toured 42 dates in the show L'album dei ricordi with the singer Carla Boni, and in December that year he was a guest on Canzonissima. His last public appearance was in the first episode of the variety show Milleluci, hosted by Mina and Raffaella Carrà, recorded in February 1974. He passed away in Rome on March 8, 1974, of a cerebral thrombosis, shortly after the recording; the episode aired on March 16. He is buried in the Flaminio cemetery in Rome beside his mother.

Rabagliati is first of all a pop and radio star, and that is stated here plainly: most of his career was Italian light song, film, revue and television, and much of his recorded catalogue is sentimental songs, Milanese dialect numbers, Latin rhythms and French chansons rather than jazz. English Wikipedia calls him a jazz singer, Italian Wikipedia calls him the first star of Italian light music, and Treccani's biographical dictionary says he was known above all for his swing numbers. The jazz thread is real and documented. He met swing and scat singing in Hollywood around 1930, sang with Barzizza's Cetra Orchestra and the Lecuona Cuban Boys, and recorded D'Anzi's rhythm songs at the moment Italian dance orchestras were absorbing American swing. Discogs files the Giorgio Gaslini album and the 1964 EP under Swing and Vocal, and anthologies of Italian jazz and swing of the 1930s and 1940s on Riviera Jazz Records and Warner include his sides alongside the Trio Lescano and Natalino Otto. On the records his approach is that of a dance-band vocalist singing swing songs, not an improviser, and he is best understood as a central voice of how swing reached an Italian mass audience.