Carlsen, born in Denmark, studied architecture for four years before coming to the United States in 1872. After a brief, unsatisfying apprenticeship in architecture, he turned to painting studying briefly under Danish painter Laurits Holst. He was, however, primarily a self-taught painter; he eventually became one of New England's most successful still-life and seascape artists. He is famous for his depictions of the surf.
In 1875, Carlsen undertook European travel and study of the old masters. By 1884, with an established reputation, he was retained by a dealer. But his style was changing. After a second visit to Paris, he returned in 1886 with a lighter palette.
Carlsen spent the last part of his career in New York and Connecticut, associating with prominent American impressionists.
He is best recognized for combing traditional representational art with impressionistic approaches to color and light.