Rep. Clay Shaw (R-Fla.), right, was known for crossing party lines. He pushed for welfare reform and a missing child registry. (ALAN DIAZ/Associated Press)

E. Clay Shaw Jr., a Florida Republican who served 26 years in Congress and sponsored measures that promoted welfare reform, environmental restoration and a registry of missing children, died Sept. 10 at a hospital in his home town of Fort Lauderdale. He was 74.

A statement issued by his family said he had lung cancer.

Mr. Shaw was elected to the House of Representatives in 1980 from a district that included parts of Miami-Dade, Broward and Palm Beach counties along Florida’s southeastern coast. He was regarded as an effective, if low-key, lawmaker who was a reliable conservative voice but not as doctrinaire as other members of the House.

He had a reputation for working cordially across party lines, and several of his signature legislative achievements were signed into law by Democratic President Bill Clinton.

“He didn’t let partisanship get in the way of legislating,” Eric Eikenberg, Mr. Shaw’s former chief of staff, said Wednesday in an interview. “He found great delight in working with Democrats and Republicans alike. Washington today needs more Clay Shaws to put away the rancor and get things done.”

Soon after Mr. Shaw was elected to Congress, a 7-year-old boy from his district, Adam Walsh, disappeared and was later found murdered. The boy’s father, John Walsh, became a noted advocate for crime victims and the host of “America’s Most Wanted.”

In response to Adam’s death, Mr. Shaw sponsored the Missing Children’s Act, which President Ronald Reagan signed in 1982, authorizing law enforcement agencies to enter information about missing children into a national database. It was a major step in developing a nationwide network to assist missing and abused children.

Another of Mr. Shaw’s projects was a long-delayed effort to reform the nation’s welfare laws, which he believed destroyed families and encouraged laziness.

“If you pay someone to do nothing, many are going to sit home and do nothing, and I don’t care if that home is a mansion or a shack,” he told the Miami Herald in 1995. “It’s human nature. Welfare is the cruelest system of all. I call it the federal plantation. It’s a form of slavery.”

After the Republicans won control of the House in the 1994 elections, two welfare reform packages were approved by Congress, only to be vetoed by Clinton.

Mr. Shaw introduced a third bill — formally titled the Personal Responsibility and Work Opportunity Reconciliation Act — that was signed into law in 1996 and fulfilled a key part of Clinton’s campaign pledge to “end welfare as we know it.”

The bill, generally known as the Welfare Reform Act of 1996, imposed a five-year limit on welfare recipients and required them to seek work. The Aid to Families with Dependent Children program and other assistance programs were replaced by temporary block grants designed to move people off welfare and into the workforce.

The new law trimmed billions of dollars from the federal budget, but opponents charged Mr. Shaw and other supporters with being insensitive to the plight of the poor.

Mr. Shaw, whose district included many elderly residents, was considered one of the leading authorities on Social Security in Congress. In 2000, he sponsored a bill that repealed a Depression-era law that reduced Social Security benefits for people between 65 to 69 if they earned more than $17,000 a year.

The same year, he championed the Water Resources Development Act, a far-reaching bill that included a 30-year plan to restore the environmental integrity of the 18,000 square miles of Florida’s Everglades, near his district. Again, Mr. Shaw worked across the aisle, most notably with Sen. Bob Graham (D-Fla.), to secure the bill’s passage.

“He was from a district that had a lot of Democrats,” Susan McManus, a political scientist at the University of South Florida, said, “and he always had a willing ear to listen to his constituents.”

Mr. Shaw was narrowly returned to office in 2000, winning by 599 votes in the same election in which the presidential race in Florida between George W. Bush and Al Gore ended in the prolonged ­hanging-chad battle. Bush ultimately prevailed.

But Bush’s growing unpopularity, as well as the war in Iraq, eventually led to Mr. Shaw’s political demise. He lost his 2006 reelection bid to Democrat Ron Klein by three percentage points and entered retirement.

“There’s nothing to be ashamed of,” he told the Palm Beach Post at the time. “I wasn’t mixed up in any scandal. I tell you, 26 years and not being accused of doing anything dishonest, it’s an achievement.”

Eugene Clay Shaw Jr. was born in Miami on April 19, 1939. His father was a doctor.

He was a 1961 graduate of Stetson University in DeLand, Fla., received an MBA from the University of Alabama in 1963 and a law degree from Stetson in 1966. He practiced law and worked as a certified public accountant early in his career, but he spent most of his career in public life.

He was a city prosecutor and municipal judge before winning election to the Fort Lauderdale City Commission in 1971. He was the city’s mayor from 1975 until he entered Congress in 1981.

In 2003 and 2005, Mr. Shaw was treated for lung cancer, even though he was a nonsmoker.

Survivors include his wife of 53 years, Emilie Costar Shaw of Fort Lauderdale; four children; and 15 grandchildren.

When Mr. Shaw was a judge in Fort Lauderdale, one of the lawyers who appeared in his courtroom was Alcee L. Hastings, a liberal Democrat who now represents a nearby congressional district. Despite their political differences, they became good friends.

“Very easy to talk to,” Hastings told the Miami Herald in 1995. “Always has been. He isn’t a down-and-dirty type of politician. I believe if Clay tells me something, I can trust him.”