Born in Warsaw, Poland, Roberti was the daughter of a clown and as a child performed in the circus as a trapeze artist, and as a vaudeville singer. As the family toured Europe and Asia, Roberti's mother left her husband, settling in Shanghai, China where the younger Roberti earned money singing. They moved to the United States in the late 1920s where Roberti began singing in nightclubs. She made her Broadway debut in You Said It in 1931, and with its success became an overnight sensation.

She moved to Hollywood and during the 1930s played in a string of films. Her sexy but playful characterisations, along with the unusual accent she had acquired during her years in Europe and Asia, made her popular with audiences. She found success as a comedienne, and was also popular as a singer on radio. In Roberta (1935), Ginger Rogers played the role that Roberti had originated on Broadway, with reviewers commenting that Rogers' performance was a completely accurate imitation of Roberti's idiosyncratic speech and mannerisms.

Roberti replaced Thelma Todd in a couple of films after the death of Todd, but her health was failing due to heart disease. She began to work less frequently although two days before her death she performed a radio show with Al Jolson.

Roberti died from a heart attack while bending to tie her shoelace. She is interred in the Forest Lawn Memorial Park Cemetery in Glendale, California.