By 1890, Lawson moved to New York and commenced studies at the Art Students League under John Henry Twachtman, who had an immense impact on the young artist's work.

Devoted to landscape painting, Lawson moved to Washington Heights in Manhattan in 1898 where no buildings obstructed the view of the Hudson River, which he loved to depict. Lawson painted his most important canvases during his eight years in Washington Heights.

In 1908, Lawson participated in the landmark exhibition of The Eight at the MacBeth Galleries in New York, despite his stylistic separation from the Ashcan aesthetic of Robert Henri and his circle. Lawson also participated in such monumental exhibitions as the 1913 Armory Show and the 1915 Panama-Pacific Exhibition.

Part of a group of New York painters called "The Eight," he was fascinated by the urban environment of early 20th-century New York. His style was close to pure Impressionism, and many of his works focus on the influence of human beings on the landscapes, quite often with the suggestion that someone has just been a part of the scene.

Lawson suffered financial difficulties late in his career despite his renowned reputation. In 1936, suffering from rheumatoid arthritis which allowed him to paint only intermittently, Lawson settled in Coral Gables Florida. In 1939, Lawson's dead body was found on the beach. It is unclear whether he suffered a heart attack, committed suicide, or was the victim of an attack on the beach on the morning of December 18th.