He feels that experimenting with a variety of mediums has helped him appreciate many different forms of art. This in turn enhances his own work. Constantly challenging himself has translated into a successful career in fine art encompassing several one-man shows and participation in group exhibitions across America including Denver Rotary Club's "Artists of America", Colorado Governor's Invitational Art Show, The Pastel Society of America, and the Salmugundi Club in New York City. O'Hagan has also participated in group exhibitions in Japan, China, and France. He is a Master Pastelist with the Pastel Society of America, and is listed in Who's Who in American Art and Who's Who in America.
O'Hagan has won awards at the Pastel Society of America's annual shows in New York City including the Mrs. Pearl Kalikow Award, Hudson Valley Art Association Award, and the Connecticut Pastel Society Award. He has also won the George Innes, Jr. Memorial Award from the Salmagundi Club. At the 1999 International Association of Pastel Societies Exhibition held in Albuquerque, New Mexico, O'Hagan was awarded the Prix'd Pastel Award (Best of Show). In May 2005, he was inducted into the International Association of Pastel Societies' "Master Circle". His art has been the subject of feature articles in numerous magazines including "American Art Collector" (May 2007), "The Artist's Magazine" (May 2005, Sept. 2001, and Sept. 1995), "International Artist" (Jan/Feb 2001), "Southwest Art" (Feb. 2004, April 2002, and Nov. 1987), "The Artist" (Great Britain, August 2006), "Irish America" (April/May 2003), "The Pastel Journal" (May/June 2003), "American Artist" (December 1989), "Artists and Illustrators" (England, October 1998), "Gekkan Bijyutsu Art Magazine" (Japan, May 1998), "Denver Business Journal" (August 2004), and United Airlines' "Hemispheres" magazine (January 1996).
O'Hagan's paintings have also been featured in a number of books including "Painting with Pastels" by Maggie Price, Rockport Publisher's "The Best of Oil Painting" and "The Best of Pastel", and Quarry Books' "The Best of Pastel 2". His art is in public and private collections in the United States, Japan, Canada, and Europe. O'Hagan's paintings are represented by galleries in Denver, Colorado, Santa Fe, New Mexico, Los Angeles, California, Vail, Colorado, Chicago, Illinois, Huntsville, Utah, and Burlingame, California. In addition, O'Hagan displays and sells his work through this website and his studio in Denver, Colorado. O'Hagan also conducts workshops occasionally through a variety of organizations.