"Mona Lisa" was the first song not performed in English to win an Oscar for Best Song. Amazingly, it was more than fifty years before another foreign language composition took the gold. As of 2020, only two songs have accomplished the feat: "Al Otro Lado Del Rio" from The Motorcycle Diaries (2004) and "Jai Ho" from Slumdog Millionaire (2008).
Although set in post-war Italy and featuring an important local Italian family, none of the 5 featured actors is Italian. Joseph Calleia (Dr. Lunati) is Maltese; Richard Avonde (Carlo) is Canadian, Celia Lovsky (Contessa) and Francis Lederer (Baron Rocco) were born in what was Austria-Hungary; and Wanda Hendrix (Baronessa Giulia) is from Jacksonville, FL.
"Mona Lisa" was initially written off as a dark horse for winning the Best Song Oscar, as no composition from a non-musical picture had ever accomplished the feat. At the time, the song was considered a throwaway moment in Captain Carey, U.S.A. (1950) that lassoed a nod only because 1950 was a slow year for musicals. Paramount obviously did not conceive of a nomination, as the song didn't even receive a screen credit for its composers, Ray Evans and Jay Livingston. On the evening of the awards, "Mona Lisa"'s win was a genuine upset, beating out "Be My Love" from The Toast of New Orleans (1950), "Bibbidi-Bobbidi-Boo" from Walt Disney's Cinderella (1950), "Mule Train" from Singing Guns (1950) and "Wilhelmina" from Wabash Avenue (1950).
For decades, confusion has surrounded the film's Oscar win for Best Song, as the official release year was 1949, while the statuette was bestowed for the year 1950. In an unusual twist for a Hollywood product, Captain Carey, U.S.A. (1950) premiered in London in late 1949, not opening in the U.S. until the turn of the year, in February 1950. As such, its American premiere date dictated its Oscar eligibility for the year 1950.
Fans expecting to hear the Oscar-winning "Mona Lisa" in the romantic vein later immortalized by Nat King Cole are often disappointed to discover that the song is in fact intricately woven into the plot, performed in Italian, serving as a secret code the soldiers use to signal imminent danger to one another. It then resurfaces several times as an accordion solo designed to trigger Carey's traumatic wartime memories.