John Buckley graduated from Malden High School and earned a business degree from Boston College, later attending Saint John's Seminary. He began his career as a publishers representative before transitioning into politics. Buckley switched from the Democratic to the Republican Party in the mid-1960s and ran for Massachusetts State Auditor, though he was unsuccessful. He was appointed sheriff by Governor Francis W. Sargent and later elected to a full term, demonstrating his ability to secure and maintain public office. Buckley's career included a brief foray into gubernatorial politics and a congressional race, showcasing his ambition and adaptability in various political arenas.

John Buckley’s political identity is marked by a blend of progressive stances on criminal justice and a critical view of traditional government structures. His opposition to the death penalty and support for gun control juxtapose with his role in a traditionally conservative party, hinting at an ideologically agile approach. Buckley’s efforts to improve conditions for inmates, such as eliminating mail censorship and allowing conjugal visits, reveal a surprising commitment to rehabilitation. His sharp criticism of county government as "a patronage-ridden system" underscores a desire for systemic reform, making his political philosophy both intriguing and conceptually rich.