He began studying marble sculpting at the age of 9 with the monks of San Domenico and with sculptor Tito Sarrocchi, whose studio was in the cloister of the church in Siena.
In about 1879, a Dalmatian sculptor, Ivan Rendić, who saw his work was impressed and invited Moretti to assist him in his studio in Zagreb, Croatia.
Moretti decided to leave, moving to Vienna, Austria,[3] where he worked on the Rothschild palace[2] and executed a marble bust of the Emperor Franz Josef which was to be exhibited in the Paris Exposition of 1900.
[2] Soon, Moretti was working on his first commission in America, sculpture for Marble House, the seasonal residence of William K. and Alva Vanderbilt in Newport, Rhode Island.
On this project, Moretti worked with Richard Morris Hunt to produce the interior's marble friezes and statuary, including work on bas-reliefs of the architect himself and Jules Hardouin Mansart, the master architect for Louis XIV during the construction of Palace of Versailles; and which stood side by side on the mezzanine level of the staircase.
By 1900, the foundry had relocated from Manhattan to Brooklyn, secured the financial backing of Piva once again, and acquired the exclusive casting rights to the works of American sculptor Frederic Remington.
[3] Despite his financial misdealings, Moretti retained his reputation as an artist, and soon won his most famous commission from James A. MacKnight, secretary of Birmingham, Alabama's Commercial Club.
[5][6] Having discovered Alabama's rich marble deposits, Moretti made it a personal goal to institute proper mining procedures for the material.
Moretti moved around east of the Mississippi frequently after 1916, returning to Pittsburgh, where he established a permanent residence and studio on Bigelow Boulevard.
[2][3] Moretti soon made war memorials a major source of his income, completing sculptures and tablets in Ohio, Pennsylvania, and elsewhere.
Moretti's notable work in Pittsburgh includes the Highland Avenue entrance to Highland Park, an imposing granite construction decorated with bronze groups and figures; the Stanton Avenue entrance to Highland Park, depicting two groups of lean, heroic youths taming wild horses; the four bronze Panthers erected on Panther Hollow Bridge; and Stephen Foster, a tribute to the songwriter which features a rendering of "Old Black Joe" playing the banjo at the feet of the composer.
"[10] He also sculpted a baptismal font for the 1st Presbyterian Church of Birmingham; a life-size Sylacauga marble statue of Mary Cahalan, a beloved public school teacher; and a larger than life-size bronze statue of William Elias B. Davis, a noted surgeon and co-founder of the Southern Surgical Association.