Machacek was born in Cedar Rapids, Iowa. Working for The Times-Union of Rochester, New York, in 1971, he and Richard Cooper covered the Attica Prison riot. Their reporting was recognized with the 1972 Pulitzer Prize for Spot Reporting.
- "Pulitzer Prize-winning reporter John Machacek, who covered Attica prison violence, dies". Democrat and Chronicle. Rochester, New York: Gannett Company. pp. 1A, 7A. Retrieved 29 July 2020.
- "Local General or Spot News Reporting". The Pulitzer Prizes. Retrieved 28 October 2013.
- Brennan, Elizabeth A.; Clarage, Elizabeth C. (1999). Who's who of Pulitzer Prize winners. Greenwood Publishing Group. p. 368. ISBN 978-1-57356-111-2. Retrieved 3 August 2010.