WASHINGTON — As he often did, Dr. Robert C. Smith was hammering away at his bosses at the Food and Drug Administration in the most caustic of terms at a meeting to address his concerns about the approval of medical devices.


With seven fellow scientists seated behind him in support, Dr. Smith charged that managers “are not following the law, not following the science, not following F.D.A. core values,” according to notes of the 2008 session. He glared at a supervisor, who sat fuming in front of him.


Dr. Smith — radiologist, lawyer, litigant and the man now at the center of a spying scandal at the F.D.A. — is in some ways typical of that peculiar Washington phenomenon known as the whistle-blower: He pressed charges of government abuse, battled with his bosses, and ultimately was shown the door amid lawsuits and investigations.


But he took his role to an extreme, according to former colleagues, scorning negotiations, making enemies of critics and papering Washington with complaints, which helped sow chaos at the agency. One co-worker compared his efforts to “a mutiny.”


This month, F.D.A. officials came under fire from Congress after disclosures that they had begun a surveillance operation monitoring the e-mail of Dr. Smith and four other employees as they wrote to their lawyers, lawmakers and even President Obama. Dr. Smith’s scorched-earth tactics had so unnerved managers that they, too, resorted to extreme measures, and the monitors ended up producing a sort of enemies list of 21 agency critics, including Congressional officials, academics and journalists.


Some 80,000 pages of documents intercepted in the spy operation — many of them e-mails from Dr. Smith seeking help from scientists, politicians, reporters, academics and others — detail his campaign to expose what he claimed were harmful practices at the F.D.A. The documents, accidentally posted online by an F.D.A. contractor, reveal a four-year process of estrangement between Dr. Smith and his bosses.


At first, F.D.A. managers sought to appease him by restructuring his office, calling in mediators and pledging reforms. But he responded with more sweeping charges of wrongdoing, accusing agency officials and manufacturers of a criminal conspiracy to market unsafe devices. An outside consultant said his vitriolic attacks created a toxic workplace.


Dr. Smith stood to profit from his accusations: he and other disgruntled F.D.A. scientists had filed a lawsuit, kept secret under court seal by law, against manufacturers of imaging devices. After discovering the suit, F.D.A. officials began to suspect his motives. Those suspicions intensified when they learned that he had filed similar whistle-blowing lawsuits against two previous employers, Yale and Cornell.


The Brooklyn-born Dr. Smith, 52, who left the drug agency in 2010 and is now working as a radiologist at a private practice in Great Neck, N.Y., does not apologize for his aggressive style. “I’m not the kind of guy who ever in his life turns a blind eye to things,” he said in an interview.


His concerns about the effectiveness of certain imaging devices for detecting breast and colon cancer are shared by some medical experts. But potential allies were driven off by his abrasive style. “He got annoying, he got obstructive in nature,” said Dr. Carl D’Orsi, a mammography expert at Emory University who worked on an F.D.A. review panel and also served as a consultant for a manufacturer. Fellow employees went further, complaining to the consultant that Dr. Smith was “disruptive,” “adversarial” and “confrontational.”


Staff members for three Congressional committees that often criticize the F.D.A. reviewed Dr. Smith’s complaints and chose not to pursue them. The inspector general of the Department of Health and Human Services examined his claim that the agency was violating the law in reviewing medical devices and concluded that he was wrong.


Dr. Smith maintains that many imaging devices do not work as advertised by their manufacturers, produce many false positives and subject patients to needless rounds of potentially harmful radiological testing. Moreover, he says they waste enormous amounts of federal Medicare aid. Dr. Smith said that his sole goal in making his complaints was to protect Americans from harmful medical devices and that money was not a motive.


His concerns are now getting another look. The Office of Special Counsel, which investigates whistle-blower grievances, found in a confidential review this spring that Dr. Smith’s allegations raised a “substantial likelihood” of serious problems and required a full review. That has triggered an investigation by Kathleen Sebelius, the secretary of health and human services.