After emigrating to Paris in 1931, then to Spain in 1932 and spending a brief time in London (1934–35), Bucovich emigrated to New York in 1935. During his American period, he self-published two photobooks: Washington D.C. and Manhattan Magic. A Collection of Eighty-Five Photographs. During his time in New York, Bucovich also had a studio at 687 Lexington Avenue and advertised his portrait services in The New Yorker, perhaps looking to duplicate the strategies developed in London to New York, attracting a wealthier clientele. New York was not new to him as he had lived there with his wife Marie Bucovich from 1909 to 1910, working as an engineer for the Otis Elevator Company. When he returned in 1935, the city was completely transformed, with buildings such as the newly erected Woolworth Building (1913), 40 Wall Street, the Chrysler Building (1930) and the Empire State Building (1931).

Before emigrating to New York in 1935, Bucovich had already lived a peripatetic life, travelling throughout the world, to Paris, London, Spain, Berlin and, in the early 1900s, also New York (Berkowitz; Köhn 2014). He was born in Pula in the Istrian region of the Austro-Hungarian Empire and grew up enjoying the comfort and mobility of a late Habsburg aristocrat, his father being Baron August Freiherr von Bucovich. In the 1920s Bucovich worked primarily in Berlin at the Atelier Karl Schenker (Berlin), where he photographed personalities of the Weimar period such as the actress Elisabeth Bergner and Marlene Dietrich. Between 1925 and 1930 Mario and Marie Bucovich ran Karl Schenker‘s studio on Budapester Strasse 6 in Berlin. During the late 1920s his portraits appeared in German magazines including Der Querschnitt, Uhu, Die Dame or the French magazine Paris, where in 1933 a photograph by him was the cover. From March 1927 until March 1928 his portraits, city and architecture scenes were exhibited at Friedmann & Weber in Berlin. A review of the exhibition says: "The architectures and city views are excellent. Less convincing are the portraits. There is much in them that is deliberately blurred, perfumed, and sweet.“ (Scheffler 1927)

At the end of the 1920s he reoriented his photographic practice, focusing on street scenes and urban topics and found recognition in avant-garde circles. In 1928 two photobooks, which were part of the series Das Gesicht der Städte, were edited with photographs by Mario Bucovich: Berlin 1928 (Albertus, 1928), with a foreword by Alfred Döblin, and Paris (Albertus 1928), with a foreword by Paul Morand and in which several images by the photographer Florence Henri were also reproduced. His street and city photographs, which were often in the aesthetics of the New Vision, were also shown at the Fotografie der Gegenwart exhibition at the Folkwang Museum in Essen in 1929, and were entered in an international photographic competition held by the Brooklyn Institute of Art and Science, which Bucovich won with a portrait of Lilli Darvas. (Anonymous 1928, 4)

The hope of further opportunities for his work in Berlin probably prompted Bucovich to apply for German citizenship in January 1929, but this failed because he was unable to settle an outstanding tax debt at short notice. Therefore, he emigrated to Paris in 1931, where he opened a portrait studio. Between July 1932 and March 1934, he lived in Spain.
At this time, a new form of tourism advertising was developing in Spain, which now included a greater use of photographic material by the publications concerned and so offered interested photographers a new and commercially attractive field of work, such as for Esplai magazine, where Bucovich's photographs featured both on the cover and inside the 8 April and 12 August 1934 issues. In the same year, he moved to London, where he was part of an exhibition at Sunderland House and published several works in the photographic magazine The Studio. In 1935 he published the book Photographs. 100 Selected Prints (Hamilton Studies, 1935), a volume presenting a cross-section of his photographic work to date: cityscapes and landscapes from his Berlin years as well as from his time in Spain, older portraits and recent photographs of members of the London upper class, which together reveal a certain objectification of his style.

Bucovich married four times. His first wife, Marie Bucovich, accompanied him on his first stay in New York. During the 1930s he was married to Anna Bucovich (nee Anna Kirstein), with whom he lived in Berlin and Paris and emigrated to New York. Renee Bucovich and Fiona (née Macbeth) Bucovich, who he married after moving to Mexico, were his other two wives. Unfortunately, very few details are known of these women. An article on Anna Bucovich in The Leader Post (16 November 1945) mentions her working at the Office of War Information where she broadcast on the American news under the pseudonym ‘Anna Buerger’ five times a week. Because of the time difference, the broadcasts were recorded and then sent shortwave to Germany (Anonymous 1945, 8). Fiona Bucovich worked for the British Intelligence service during the Second World War. (Berkowitz / Todd 2017)

In 1939, Bucovich emigrated to Mexico City, where he worked as a photographer until his death on 30 November 1947 in a traffic accident in Mexico City (Anonymous 1947, 2). During his time in Mexico, he produced a portrait series on the Russian émigré Leon Trotsky. (Anonymous 1940, 69) The series was in colour, which was very progressive for the time since colour photography was expensive and used mostly for commercial work. Further work was the Mexico Lindo series which was reproduced in colour lithograph as artwork reproductions. While in Mexico, Bucovitch maintained his US networks and his prints also appeared in the American Popular Photography magazine in the November, 1945 issue.