He was also one of the original founding general editors of the award-winning Wiley-Blackwell's Encyclopedia of Ancient History, in 13 volumes (print edition published in 2013).
The Canadian Journal of History described Champion's book as a "remarkable achievement" and "enormous accomplishment" on Greek historiography.
6) noted: “Eckstein’s Moral Vision in the Histories of Polybius (1995) opened the door for a fresh wave of Polybian scholarship by showing that Polybius’ text, rather than presenting a purely might-is-right, or ‘Macchiavellian’, view of the world, in fact attempts to represent for the reader important moral lessons that are distinct from practical utility.
These fresh demonstrations of the complexity of Polybius’ work generated an explosion of interest in this historian over the next decade.” Champion's second book, The Peace of the Gods: Elite Religious Practices in the Middle Roman Republic, was published in 2017 by the Princeton University Press.
Dan-el Padilla Peralta, a professor of Classics at Princeton University, wrote in his review of the book in the journal Histos: "I want to conclude by stressing that Champion has written a remarkable book that will embolden future scholars to make fuller use of scientific literature.
[The] book’s capacity to spark disagreement is ocular proof of its overall success, and there is no doubt in my mind that The Peace of the Gods deserves to occupy a position of prominence in Roman religious studies for the foreseeable future."
In the American Historical Review, Federico Santangelo writes, "[The] discussion of ‘cognitive dissonance’ in Roman religion is the most advanced attempt to date to explore its viability in this field.
Champion is currently finishing up two large projects, a new book titled Citizen and Empire in Democratic Athens, Republican Rome, and Twenty-First Century America, and a two-volume, critical edition of Polybius titled, The Landmark Edition of Polybius' Histories.