‘There we four —   my new cronies — Allen Tupper True, George Harding, Gordon McCouch and I — made our first sketches, from a model, and our effots were frightful to behold! Not one of us had had a palette in our hands ever before: I had not the least idea as to prceedure.  My attempts were terrifying to behold, and when H.P. came to me to criticise my work, he paused for a long, long time before speaking, and I know that he most have been appalled.”
Oakley studied with Pyle for three years.

Oakley became an illustrator and writer for periodicals, including Scriliner’s, Century, Colliers, and Harper’s Mo,thlY. In the years 1014 10 arid IQ_2L 36 he was in charge of the Department of Illustration at the Philadelphia Museum School of Industrial Art. In 1914 15 he also taught drawing at the University of Pennsylvania, and gave lectures at the Art Institute of Chicago, the Metropolitan Museum of Art, and the Curtis Institute. He was a member of the jury of selection and advisory committee of the Department of Fine Arts at the Panama Pacific International Exposition in San Francisco in 1915 and the Philadelphia Sesquicentennial Exposition in 1926.

During World War I lithographs of his patriotic drawings of war work at the Hog Island Shipyard, Pennsylvania, were distributed by the United States government. During World War II he did three sets of pictures of the war effort for the National Geographic in 1941, 1943, and 1945. After the war he was commissioned to paint industrial subjects for the Pennsylvania Railroad, the Philadelphia Electric Company, Sun Oil, and other industries. In 1938-39 he did six mural panels for the Franklin Institute in Philadelphia on epochs in science.

Oakley was deeply influenced by Howard Pyle’s philosophy of illustration. In the taZ at the Free Library referred to above, he said; “We never heard one word from our beloved teacher concerning tools and methods. His utterances were only of the spirit, thought, philosophy, ideals, vision, purpose.” Oakley presided at the private viewing of the Howard Pyle Memorial Exhibition at the Philadelphia Art Alliance in 1923, when reminiscences of Pyle were given by Elizabeth Green Elliott, Jessie ivillco, Smith, George Harding, and Frank E. Schoonover. In praising Pide, Oakle) said: “Illustration is the highest type of pictorial art … because illustration is simply a pictorial MAKING CLEAR, and if a picture makes clear a message in a big way, it is an illustration, whether it be made for magazine, book, mural decoration, or exhibition.” In an essay on “Illustration” for the American Magazine of Art in August 1919, he spoke of illustration as inspiration and the expression of man’s highest ideals.