After graduating from Lehigh University in 1967 with a degree in mechanical engineering, Spinney started his first post working in the flight dynamics lab at Wright-Patterson Air Force Base in Ohio, the very base where he was born. His job was to study the effects of bullets on fighter planes shot down in Vietnam. From the start, he was known as a "brash young officer" and a "smart-ass lieutenant" but at the same time, hard working and responsible.

In 1977, Chuck Spinney joined the Pentagon's Office of Program Analysis and Evaluation (a division set up in 1961 to make independent evaluations of Pentagon policy) to work with John Boyd who, with his open contempt for authority, had become somewhat of a mentor to Spinney.

Not long thereafter, Spinney began work on what became his "Defense Facts of Life," commonly known as the "Spinney Report," said to be one of the most important documents ever to come out of the Pentagon. In it, Spinney wrote that the pursuit of complex and expensive weapon systems was wrecking the budget.

Word of Spinney's bold report and his updates over the next few years quickly spread within the Air Force. In response to his 1982 report, according to THE WALL STREET JOURNAL, at least one top Pentagon official contended that the report "contain[ed] data that [was] flawed and dated and that figures [were] under revision." But all of Spinney's information was based on Pentagon documents and was confirmed by the Pentagon to be accurate.

Spinney's superiors were hesitant to give in to pressure to made the report public. In 1983, Senator Chuck Grassley and others called on Spinney to testify before the Senate Budget Committee but Secretary of Defense Caspar W. Weinberger and director of the Program Analysis and Evaluation Office (and Spinney's boss) David S.C. Chu initially resisted this request, claiming that the study was only a "purely historical." On threat of subpoena, however, Spinney was allowed to brief the Senate committee, with Chu on hand to present a rebuttal. The hearing was scheduled for a Friday afternoon, where Spinney's critics hoped it would get little press coverage.

As reported in the BALTIMORE SUN years later,

The weekend came and went with only a smattering of news stories, and on Monday, Defense Secretary Caspar W. Weinberger gathered his staff for a morning meeting. As they congratulated one another for getting through Spinney's hearing with a minimum of news media coverage, somebody walked in and tossed a copy of TIME magazine on the table. Jaws dropped. On the cover: a painting of Chuck Spinney and the words, "Are Billions Being Wasted?"

The fact that Spinney's report was unpopular with Pentagon staff was well-documented. In August 1984, THE WASHINGTON POST reported that a draft evaluation report gave Spinney a rating of "fully satisfactory," a black mark below the grade of "outstanding" or "exceptional" that Spinney felt he deserved. As Spinney recounts in his interview with Bill Moyers,

I decided to nip it in the bud. I had several of my friends go in and talk to these guys. They all… the two guys admitted that they were being pressured to reduce my performance rating, it was unfair. So essentially we had a case for a conspiracy to do an illegal act because it's illegal to take retribution to a person who just appeared before Congress, who had testified to Congress…. We created a stink and they backed off. And actually, they actually increased my performance rating after it was all over.

Allegedly due in part to Spinney's reports, in 1985, Congress imposed a freeze on defense spending. But this was far from the end of his battle. Right up to the present day, Spinney has continued to speak out about what he views as irresponsible choices in defense spending.

A series of articles written for THE WASHINGTON POST by Spinney chronicled his findings over the next few years. In October 1988's "Look What $2 Trillion Didn't Buy for Defense," Spinney summarized his defense spending philosophy, criticized the government's obsession with defense spending as a distraction from meeting more pressing military needs and fulfilling Constitutional responsibility to account for expenditures.

In April of 1989, in "Shape Up and Fly Right: How to Build a Better Air Force for Less Money," Spinney wrote that a combination of base closings, consolidating squadrons, and relying more on reserve forces would be effective solutions for lowering the Air Force's operating costs. The Air Force later said in a rebuttal in AIR FORCE TIMES that Spinney was neither "serious" nor "professional."

Later that year, "Teach the Pentagon to Think Before It Spends" examined the Pentagon's five year plans. Spinney wrote:

The Pentagon's strategists produce budgets that simply cannot be executed because they assume a defense strategy depends only on goals and threats. Strategy, however, is about possibilities, not hopes and dreams. By ignoring costs, U.S. strategists abdicate their responsibility for hard decisions.

Senator Grassley has remained a great advocate of Spinney's work. In 1995, he delivered an impassioned speech appealing to President Clinton and demanding the Pentagon reform its accounting mess, citing Spinney's findings.

Spinney continues to find flaws in the defense spending of the current Bush administration. In a DEFENSE WEEK commentary in September 2000, Spinney responded to calls for the defense budget to be increased from 2.9% of the GDP to 4%, claiming that such a move "would be tantamount to a declaration of total war on Social Security and Medicare in the following decade." A later commentary by Spinney criticized the Pentagon for not passing the previous four annual audits.

Spinney's most recent appearance in Congress was as recent as 2002, when he testified before the Subcommittee on National Security, Veterans Affairs and International Relations, part of the House Committee on Government Reform on Pentagon accounting and the increasing defense budget before 9/11. See Spinney's statement.