As a municipal historian and independent historian, Sweeney researches, educates, promotes, and celebrates the history and architecture of Historic Homer, New York, which includes two Historic Districts: Old Homer Village and Glenwood Cemetery.

Besides two articles in The New York History Review and a regular column in The Homer News, Sweeney has published two works of historical non-fiction. Lincoln's Gift from Homer, New York: A Painter, an Editor, and a Detective tells the story of three native-sons of Homer with significant ties to the life and legacy of President Abraham Lincoln: Francis Bicknell Carpenter, William Osborn Stoddard, and Eli DeVoe. Death in the Winter Solstice: A Narrative of a True Murder Mystery in Homer was published as a fundraiser for the Cortland County Historical Society and describes the unsolved murder of Patrick Quinlan in 1894. Inspired by this "cold case" from Homer's past, Sweeney wrote a work of historical fiction, The Suffragette's Saga: A Murder Mystery. This is scheduled for release in early 2019.