T.J. Gaffney was born and raised in the Port Huron, Michigan, area. After receiving his Bachelor’s Degree in history from Denison University, he studied at Clemson University, where he received his Master’s Degree in American transportation history. He returned to the Port Huron area in 1999 and joined the staff of the Port Huron Museum as the Curator of Collections in 2000. In 2006, he authored his first book, Port Huron, 1880–1960, based in large part on the postcard collection his father, Thomas John Gaffney, had collected for over 40 years. During this time, he also became an adjunct professor at Baker College.

In late 2006, Gaffney became the executive director of the Steam Railroading Institute in Owosso, Michigan, a position he held until 2011. That same year, Gaffney opened up an antique and historical consulting and appraisal business known as Streamline Historic Services, and authored his second book Images of Rail: Rails Around the Thumb.

TJ is the proud father and husband of children Thomas and Phoebe and wife Heather. He is currently co-authoring a third book with Dean Pyers for Arcadia publishing, titled Pere Marquette 1225. Gaffney writes a monthly article in The Lakeshore Guardian titled Thumb Rails, which details the fascinating history of railroad operations in the Thumb region.