Dick Thornburgh is awarded for his work getting the ADA through Congress.

On a hot summer day nearly 25 years ago, people with disabilities were at last made equal citizens under the law — “the personal, daily equivalent of the fall of the Berlin Wall,” wrote Washington Post columnist Mary McGrory.

And it was in no small part because of Dick Thornburgh, who will be honored this week at the National Council on Disability’s meeting at the University of Pittsburgh.

The former two-term Pennsylvania governor, then U.S. attorney general in 1989, had been enlisted by the George H.W. Bush administration to negotiate with Congress over legislation that eventually became the Americans with Disabilities Act.

Mr. Thornburgh, now 82, was probably the ideal choice to help broker a deal. He was the father of a son with disabilities — his son Peter suffered brain damage in a 1960 automobile accident when he was 4 months old — and he and his wife, Ginny, had deep connections with the disability advocacy community. A lawyer by training, a former governor and a loyal Republican, Mr. Thornburgh was asked, as he put it in a recent interview, “to be the point man to shepherd this through, to make sure we were all singing from the same sheet music in the administration and take a reasonable approach — not one that was radical or off the charts, but one that all sides could agree with.”

The ADA, Mr. Thornburgh would explain to his fellow Republicans, “was a different kind of civil rights bill — not based on quotas, preferences or set-asides” but one that stressed independence while removing barriers in the workplace, transportation, public accommodations and telecommunications. Mr. Thornburgh hammered that point home in hearings before the House and Senate in May 1989, urging a cost-benefit analysis to measure the burdens to business with the benefits of empowering persons with disabilities.

Negotiations began on July 27 of that year in the office of Republican leader Robert Dole, who’d suffered a war injury. Also present, beside Mr. Thornburgh, were White House chief of staff John Sununu, Sens. Edward Kennedy, Tom Harkin, Orrin Hatch and numerous congressional aides.

Critical sticking points included the size of businesses subject to the law’s discrimination provisions; standards for providing “reasonable accommodation” in the workplace; punitive damages in litigation; accessible transportation, telecommunication and other public accommodations.

After concessions on both sides, an agreement was reached and passed the Senate on Sept. 7.

Then the legislation went to the House, winding slowly for months through four committees. Delays prompted advocates to stage a “Capitol Crawl” on March 12, 1990, literally dragging themselves up the Capitol’s 83 front steps — much to the consternation of members of Congress. Perhaps apocryphally, advocates today call that action the tipping point for passage in the House on May 22. A final version was passed by the Senate, and it was signed by President George H.W. Bush on July 26, 1990.

“This was a very bold and radical undertaking at first look,” said Mr. Thornburgh, “but it proved to be a triumph of reason over emotion.”

The triumph was shortlived, at least in one area. Hopes that the new law would reduce unemployment, increase consumer spending and raise tax revenue were dashed in 1991 when a weak economy and job cuts discouraged employers from making the kinds of accommodations needed to employ people with disabilities.

“The one tragic shortcoming” of the ADA was “the failure to reduce the unemployment rate among people with disabilities,” Mr. Thornburgh said. A 2012 Cornell University study estimated that only about a third of 18.9 million people with disabilities are employed.

Mr. Thornburgh’s own son Peter has a full-time position with the Food Bank of Central Pennsylvania, he added, “with all the joys and challenges any of us have with our daily jobs.”

Nonetheless, his disappointment about continuing high unemployment is palpable. “We were a trifle naive in thinking that these advances would follow as a matter of course after the enactment of legislation.

“The big change is yet to come,” he said. “I’m not negative or discouraged. I’m impatient.”