He began a journalistic career in 1956 with United Press International in Newark, New Jersey and Trenton. Later he worked at The Daily Tribune in Royal Oak, Michigan, rejoined UPI for two years in Chicago, and served separate stints with Business Week, in Detroit and Pittsburgh, specializing as a labor reporter on the automobile, steel, and coal-mining industries. After five years as an on-air reporter and documentary producer at WQED, the PBS station in Pittsburgh, he returned to Business Week in 1975 as labor editor and later senior writer on the New York staff. Since 1991, he has been a free-lance writer of nonfiction and fiction.
He was born in McKeesport, Pennsylvania, a steelmaking town in the Monongahela River Valley south of Pittsburgh. He graduated from McKeesport Area High School (1948) and Penn State University (1953). During college he worked short stints in the steel works at McKeesport. Hoerr served in the U.S. Army 1953-1955 and was stationed in France. After living for more than three decades in Teaneck, New Jersey, he moved to Middleborough, Massachusetts in 2009.
- And the Wolf Finally Came: The Decline of the American Steel Industry, nonfiction (Pittsburgh: University of Pittsburgh Press, 1988).
- We Can't Eat Prestige: The Women Who Organized Harvard, nonfiction (Philadelphia: Temple University Press, 1997).
- Harry, Tom and Father Rice: Accusation and Betrayal in America's Cold War, nonfiction (Pittsburgh: University of Pittsburgh Press, 2005).
- Monongahela Dusk, novel (Pittsburgh: Autumn House Press, 2009).
- "Obituary: John P. Hoerr / Writer chronicled decline of steel industry". Post-gazette. Retrieved 16 September 2015.
- Levin, Jay. "John Hoerr, 84, chronicled the fall of steel", The Record (Bergen County), June 26, 2015. Accessed June 26, 2015. "ohn Hoerr, a journalist and former Teaneck resident, authored one of the most definitive accounts of the collapse of America's steel industry.... The Hoerrs moved to Middleborough in 2009 after 33 years in Teaneck."
Contemporary Authors Online. The Gale Group, 2008.