Macklin is a freelance film critic. A current member of the Las Vegas Film Critics Society, he is a former film and literature professor at the University of Dayton, and the former editor of the filmcrit magazine Film Heritage. His articles and reviews have been most recently featured at Rotten Tomatoes and The Internet Movie Database, as well as in the Bright Lights Film Journal and The Fayetteville Free Weekly.

His well-received book, Voices from the Set: The Film Heritage Interviews (2000), includes his 1970s interviews with Alfred Hitchcock, Howard Hawks, Martin Scorsese, Alan Rudolph, Robert Altman, Sam Peckinpah, John Wayne, Edith Head, Stockard Channing, Richard Baskin, and others.