Hall, known to "CSI" viewers as Dr. Al Robbins, the medical examiner, is also a leading advocate within the entertainment industry for the disabled, a cause he embraced in the 1980s in the years after he lost his legs when a big rig ran over his car on a Los Angeles freeway.
Most recently, his activism led him to the White House, where he introduced President Barack Obama last week at an event celebrating the 20th anniversary of the signing of the Americans with Disabilities Act.
In an interview with United Press International, Hall said he is pretty sure the fact he is an actor on a hit TV show helped get him the invitation.
But he said when he was a boy, what he really wanted to do was attend the Naval Academy, where several family members had been educated.
"That was my dream," he said.
Nearsightedness got in the way of that plan, he said.
"I think that's when I started cranking on the guitar and considering alternate careers," Hall said.
Asked if the experience provided an early life lesson in how to work around a disability, Hall said he "never thought much about disability."
Rather, he said he's just always been "a great one for (if) somebody says no (I say), 'Oh, yeah?'"
Hall, who played in cover bands in the '70s and then carved out a career as a radio DJ and voice over performer in Los Angeles, says he got involved in advocacy on behalf of the disabled during the 1980s when the issue of accessibility gained a place of greater prominence on the national political agenda.
"I was busy pursuing my career in radio, voice over and acting and I knew a lot of activists back in the early '80s," he said.
"Somebody would say hey … (demonstrators) are chaining themselves to buses downtown, and I did a few of those," Hall said. "That's what you did. You tried to show up at these things."
Hall has served for 12 years as national chairman of the Screen Actors Guild, American Federation of Radio and Television Artists, and Actors Equity committee on performers with disabilities. Twenty years after ADA was signed into law, he says he still encounters occasional accessibility barriers.
"I travel a lot. I've encountered a lot of architectural barriers. But in my opinion architectural barriers are second to barriers of attitude.
"There are a lot of studies showing huge gaps in employment and education and income for people with disabilities," he says. "I'm one of so few people with a disability in the entertainment business."
At the same time, Hall says he's "never never felt discriminated against because I was always trying to move forward."
The ADA has its detractors, primarily those who -- like Rand Paul, the Republican nominee for U.S. Senate in Kentucky -- question the wisdom of permitting the federal government to dictate the terms of accessibility to local businesses. There has been at least one attempt in Congress to roll back the law, if not repeal it, but no such effort has gained any traction on Capitol Hill.
"I'd like to see them try (to repeal it)," Hall says.
"I'm sorry, the days of not being able to get your wheelchair into a public building are over," he says. "That stuff is just not acceptable.
"We're not out there saying we have to do everything. We have to get an education and were going to participate in America. That's just the way it is."
Hall's debut CD, "Things They Don't Teach You in School," released in June, is getting airplay on non-commercial and roots/Americana radio. It is available at robertdavidhallmusic.com.