Halleran received a master’s degree in American History from the University of Kansas in 1989 and his juris doctorate from Washburn University in Topeka, Kansas in 1995. He is an adjunct instructor at Emporia State University.
Halleran is the author of both articles and a book on Masons in the American Civil War, as well as a regular column in the Scottish Rite Journal recounting the adventures of Bro. Hiram Brother, a 19th Century Mason. The stories are framed as extracts from Bro. Brother's previously undiscovered journals. Halleran is the executive editor of the Journal of the Masonic Society  and was installed as Grand Master of the Grand Lodge of Kansas AF&AM on March 22, 2014.
Halleran has presented papers at numerous scholarly conferences in the United States and England. Among these, he was featured speaker at the Battle of Gettysburg 150th Anniversary, sponsored by the Gettysburg Foundation, and presented on methods of historial research for The Quarry Project.
Awards and recognition
In 2006 he was awarded the Scottish Rite Research Society’s Albert G. Mackey Award for Excellence in Masonic Scholarship for his article on Masonic courtesy in the American Civil War, and in 2008 he received the Nova Award from Internet Lodge No. 9659.
Of his book The Better Angels of our Nature, one reviewer said, "The Better Angels of Our Nature accomplishes what few books about Freemasons are able to do: it explores the legends and long-told tall tales of the fraternity in an academic fashion, with both dispassionate analysis of the facts, and an obvious passion for the subject.". Another says, "Patriotic, kind-hearted men who embraced the Masonic brotherhood deserve exactly what Halleran delivers: clear-headed, well-sourced narrative of American Freemasonry in one of the country's darkest hours."
- "The Better Angels of our Nature: Masonic Courtesy & Relief in the American Civil War," Heredom, Vol. 14 (2006).
- "Gentlemen of the White Apron: Masonic POWS in the American Civil War," Heredom, Vol. 15 (2007).
- "Over Thar a Little Way: Masonic Mercies in the American Civil War," Ars Quatuor Coronatorum, Vol. 121 (2008).
- "Toh-MAY-toh, Toh-MAH-toh: Shibboleths Beyond the Craft", Scottish Rite Journal, (July–August, 2008).
- "Be on the Qui Vive: Cowans, Swindlers, and Con Men, Then and Now," Scottish Rite Journal, (May–June, 2009).
- The Better Angels of Our Nature: Freemasonry in the American Civil War, University of Alabama Press (2010). ISBN 978-0-8173-1695-2
- "The Widow’s Son: Lewis Armistead at Gettysburg," The Gettysburg Magazine, Vol. 43, (July, 2010).
- "The Jebusite’s Jobsite: The Masonic Significance of Ornan the Jebusite & his Threshing Floor," The Plumbline, Vol. 17, No. 2 (Summer 2010).
- "Freemasons in the Civil War," North & South Magazine, Vol. 12, No. 5 (2010).
- "'Hold on, Boys...' Freemasonry in the Border War, 1854-1865," Philalethes, Vol. 64 No. 2 (Spring 2011).
- "The Babylonian Temptation and Other Perils of Masonic Research," Journal of the Masonic Society, 13 (Summer 2011).
- Bro. Brother's Journal, Macoy Publishing (2012).
- "Bro. Brother's Journal," Scottish Rite Journal, September-October 2007
- "New Editor of the Masonic Society," 13 Dec 2012
- Gettysburg Foundation, Lectures and Events
- The Quarry Project Conference
- Internet Lodge Library of Papers
- University of Alabama Press reviews
- Chris Lazzarino, Kansas Alumni Magazine