In the article Miracle on Ice 42 Years Later, Abdon Pallasch interviews Jack O'Callahan about the "Miracle on Ice" game and about O'Callahan's life thereafter. As reported in the article:

A Boston native, O’Callahan followed up his triumph over the Russian hockey team with stints on the Chicago Blackhawks and the New Jersey Devils, then made his mark as a financial trader in Chicago, founding Beanpot Financial Services with fellow Boston native Jack Hughes.

Much more detail about Jack O'Callahan's memories and later life is found in the article.

Celebrate 'Miracle on Ice' with merchandise available at Lowsport incuding USA hockey, Jim Craig, Mike Eruzione, Jack O'Callahan, Mark Pavelich, and Dave Christian jerseys & hoodies. You'll also find several Jim Craig and Jack O'Callahan signed items. 

Source:

1. Abdon Pallasch. (19 February 2022). Miracle on Ice 42 Years Later. https://www.irishamerica.com/2022/02/1980-miracle-on-ice/