Famous Italian medievalist, philosopher and novelist Umberto Eco bears this name. He is most known in America as a novelist and has written among many other novels, "The Name of the Rose" and "Foucault's Pendulum."
Two kings of Italy bore this name: Umberto I di Savoia (1844-1900), who reigned 1878-1900, and Umberto II, his grandson, who reigned just a month in 1946.
In Italy Umberto was overused in the first years of the 20th century: it was the most popular name in Rome in 1901, the 4th in 1906 (behind Mario, Giuseppe and Giovanni), the 5th in 1911 (behind Mario, Giuseppe, Luigi and Alfredo).