Killelea's work and biography have been included along with other selected members of the American Society of Marine Artists, in the Smithsonian Institution's Library for the American Art Museum/National Portrait Gallery and have become the basis for a permanent file on him there. His watercolors have additionally been featured at the BJ Spoke Gallery in Huntington, NY, the Marineart Gallery in Manhattan, and in numerous local exhibits elsewhere on Long Island. They are currently on display at the Castello de Borghese vineyard in Cutchogue, NY, and 57 of them were featured in a major solo exhibition at the New York Mercantile Exchange in NYC. A collection of his Huntington (NY) Harbor paintings were selected to comprise the premier show at the Town of Huntington's online art exhibit, sponsored by now Long Island Congressman Steve Israel. His paintings have also been exhibited at the Frye Art Museum in Seattle, WA, the Cummer Art Museum in Jacksonville, FL, the Museum in the US Merchant Marine Academy, Kings Point, and in the Vero Beach Art Museum in Florida. Two of his paintings were part of an exhibit in the Capital Building in Washington, DC and became part of the US Navy Museum collection in Washington.

He isa member of the Board of Directors, the Exhibitions Committee and an Artist Member, as well as Chairman of the Regions Committee of the American Society of Marine Artists. He's a graduate of SUNY Farmingdale and has attended Pratt Institute and the School of Visual Arts. His work is in numerous private collections, has been reproduced on book and magazine covers, posters, prints & greeting cards and is featured in two books he wrote and illustrated about Long Island's rural North Fork.