WASHINGTON — Mark Foley had secrets.

First, whispers floated on the air about the Republican congressman’s sexual orientation, beginning in 1994 during his first House campaign. He was almost outed two years later when he voted against gay marriage. In 2003, Mr. Foley dropped a Senate bid after the rumor mill again started churning. He dismissed the speculation as “revolting and unforgivable.”

Although publicly unacknowledged, Mr. Foley’s homosexuality became known in Washington and Florida political circles. Over time, it became a defining force in his career. Mr. Foley was restlessly ambitious, but as a Republican from a state with many social conservatives, his prospects for higher office were dim. He hit the gay glass ceiling in Congress, too. Mr. Foley served nearly 12 years in Congress and was regarded as an energetic and capable lawmaker. But he barely registered on the senior GOP leadership’s radar screen. “I’ve never had a conversation with him,” the House speaker, Rep. Dennis Hastert, said. “Other than his vote on a tariff matter at one time or another, I think.”

But as Mr. Foley navigated the tricky path of being a gay Republican, another, darker secret lingered — one that he proved unable to handle: He was making sexual advances toward teenagers. For all his caution about his sexual orientation, it wasn’t that but his pursuit of underage former congressional pages that wrecked his career.

Mr. Foley’s fate was sealed when transcripts surfaced late last week of his lurid instant-message exchanges with other former pages. To some people who have known Mr. Foley for years, the details were both shocking and ironical, given his efforts to shield his private life.

The chairman of the Palm Beach County Republican Party, Sid Dinerstein, said he refused to believe early reports about the page exchanges, which he dubbed “the evil e-mails.” His wife was so stunned that she was convinced that someone had hacked into Mr. Foley’s instant-message account. “That’s how far off it was from the Mark Foley we knew,” he said.

Like most local officials, Mr. Dinerstein had known about Mr. Foley’s sexual orientation for years. He recently ran into the congressman and his longtime companion, a Palm Beach doctor, along with Mr. Foley’s sister and her husband, while dining at a local restaurant. “He didn’t introduce him as his companion,” Mr. Dinerstein said. “But I knew who he was from the whisper mill.”

The 52-year-old congressman has checked himself into an undisclosed treatment facility for alcoholism and “other behavioral problems.” His attorney, David Roth, confirmed at a Florida news conference on Tuesday that his client was gay. Mr. Roth also said Mr. Foley had been molested by a clergy member as a teenager, although the congressman wasn’t making excuses for his behavior. He described Mr. Foley as “emotionally devastated. He feels he let everyone down — his constituents, his family, his loved ones, his party, and the people he hurt.”

Mr. Foley had carved out a reputation as a gung-ho, if slightly unpredictable, mainstream Republican. After dropping out of a South Florida community college, he opened a restaurant at age 20 and won a seat on the Lake Worth city commission three years later. He was elected to the state House in 1990, the state Senate in 1992, and the U.S. House in 1994.

Mr. Foley staked out typical Florida Republican positions on such issues as immigration, agriculture, and Cuba. As widely noted in recent days, he took a particular interest in sexual crimes and portrayed himself as a protector of exploited children. Mr. Foley snagged a plum seat on the Ways and Means Committee and delved into trade and Medicare arcana. The last bill Mr. Foley introduced, on September 26, congratulated the Professional Golfers Association of America on its 90th anniversary.

He worked doggedly to please House GOP leaders by raising funds for key candidates and rounding up votes for critical bills. He rose to be a deputy whip in then-Majority Whip Tom DeLay’s organization and frequently praised the Texas Republican in public.