Fromkes was eight years old when his family emigrated to the United States. He pursued his artistic training in New York at the Cooper Union and the Academy school, where he was enrolled in the antique class, 1889 into 1893; the life class, 1890 into 1894; and the painting class 1892 into 1894. His Academy school registration record reveals what was presumably his true name: Moses Frumkes. When he made his debut in the Academy annual exhibition of 1895, it was under the name M. Fromkes, and when he next was represented, in the Autumn exhibition of 1896, the full name by which he is always known was established. He work was next seen in the annual in 1899; on all these occasions he showed portraits. Later in 1899 Fromkes went to Holland where he copied the works of Rembrandt and Hals in the Amsterdam and Haarlem museums. In 1904 he was abroad again, studying the Italian masters. On this latter trip he executed a portrait of the Papal Secretary of State, Cardinal Merry Del Val, which enter the collection of the Vatican.
Upon his return to New York he established a successful practice as a portraitist, receiving important commissions from the business and social community. During this period he developed an admiration for oriental art and often set his portraits against oriental backgrounds. Under the influence of his friend, the artist Henry Golden Dearth, however, he began to widen the scope of his subject matter to include landscape, urban street scenes, and still life. In 1918 Reinhardt Gallery, New York, presented an exhibition of his portraits, figures, and still lifes, many of which included oriental screens and figurines.
In the autumn of 1920 Fromkes sailed for Spain, also embarking on the phase of his career for which he would be most recognized. He took a studio in Madrid and instead of painting popular subjects such as bullfighters and flamenco dancers, sought out native types, focusing particularly on women and children. He also did still lifes that often featured gothic carvings. These works were enthusiastically received by the Spanish critic, and in 1924 an exhibition of them was held at Madrid's National Museum of Modern Art. The Museum acquired for its permanent collection A Madonna of the Road from the exhibition. Later in the same year Fromkes's Spanish paintings were shown in New York at the Milch Galleries, and then toured to other American cities. The Spanish paintings were again a featured exhibition at Arnold Seligman's Gallery in Paris, in 1927. This show then toured Spain and the United States, and finally was presented at the International Exhibition of Fine Arts in Bordeaux, France. Fromkes remained a faithful participant in Academy exhibitions from the early years of the twentieth century through 1930.