For more than three decades, Michael J. Fox has lived with a disease that has slowly demanded more from him.

More patience.

More resilience.

More physical effort simply to do things that once came naturally.

Now, at 65, the Back to the Future star is acknowledging a painful truth about his battle with Parkinson’s disease: life with the condition has become harder.

“Of course, things have gotten harder over the years,” Fox said in a new interview with People.

It is a quietly devastating admission from an actor whose public battle with Parkinson’s has inspired millions.

But Fox did not stop there.

Instead, he immediately turned toward the mission that has defined much of the second half of his life.

“I’m privileged to commit my time and energy to bringing everything I’ve got to help cure this disease,” he said.

Fox’s words arrive during an extraordinary moment in his journey.

He is being honored with the prestigious Lasker-Bloomberg Public Service Award for his decades of advocacy and fundraising for Parkinson’s research. Since establishing the Michael J. Fox Foundation in 2000, the organization has raised more than $3 billion toward research and efforts to accelerate better treatments.

And despite the worsening realities of his own illness, Fox believes scientists are getting closer.

“We’re getting close,” he told People about the possibility of breakthroughs in treating — and ultimately defeating — Parkinson’s.

That hope has carried Fox through an extraordinary personal transformation.

Millions first knew him as Alex P. Keaton on Family Ties and then as Marty McFly, the teenager who raced through time in a DeLorean in Back to the Future.

At the height of his fame, few people knew that Fox was facing something profoundly frightening off-camera.

He was diagnosed with young-onset Parkinson’s disease in 1991 when he was just 29 years old.

For years, he kept the diagnosis private.

Eventually, he made it public in 1998 and began using his celebrity for something far larger than entertainment.

By 2000, the Michael J. Fox Foundation had been established.

What followed was one of the most significant celebrity-led medical advocacy efforts of the modern era.

Fox has pushed researchers, donors, pharmaceutical companies and policymakers toward one objective: finding better treatments and eventually ending Parkinson’s.

His foundation has since become an enormous force in Parkinson’s research, financing scientific work around the world. Earlier this year, Fox said the organization had already funded more than $2.5 billion in research, more annually than the federal government directs toward some comparable Parkinson’s research efforts.

But none of that has shielded him from the disease itself.

Parkinson’s is progressive.

For Fox, the years have brought increasing mobility problems, falls and other physical challenges.

He has spoken publicly before about breaking bones after falls and about the realities of losing abilities he once took for granted.

And yet something unexpected happened this year.

Michael J. Fox went back to work.

After largely stepping away from acting, he returned to television in the third season of Apple TV’s Shrinking.

The role carried a powerful layer of reality.

Fox plays Gerry, a character who also lives with Parkinson’s disease.

“This new character allows me to show up on set as myself,” Fox said.

The series already has another major connection to Parkinson’s.

Harrison Ford plays therapist Paul Rhoades, who is navigating his own diagnosis with the disease.

Putting Ford and Fox together created scenes that carried an emotional weight extending far beyond fiction.

Fox’s return was not merely a nostalgic cameo from one of the most beloved stars of the 1980s.

It was a man living with Parkinson’s stepping back in front of the camera and allowing the reality of the illness to become part of his performance.

Apple confirmed Fox’s guest appearance in Shrinking Season 3 and celebrated his surprise appearance alongside Ford and the rest of the cast at the show’s PaleyFest finale event in April.

Fox has never pretended that optimism means denying reality.

His version of hope has always been more complicated.

It acknowledges that Parkinson’s progresses.

It acknowledges that his body has changed.

It acknowledges that tomorrow may be physically more difficult than today.

But it refuses to accept that difficulty means surrender.

That attitude is now being backed by another enormous commitment.

The Michael J. Fox Foundation is launching a new multibillion-dollar fundraising effort intended to accelerate the next generation of Parkinson’s breakthroughs.

Fox may never personally benefit from every discovery his organization helps make.

He knows that.

Yet he continues.

Because the fight stopped being only about Michael J. Fox a long time ago.

It became about millions of people living with Parkinson’s today — and millions more who could face it in the future.

At 65, Fox can no longer honestly say the disease has become easier.

It has not.

He says the opposite.

But after decades of tremors, falls, setbacks and uncertainty, the actor who once traveled through time on screen is still looking relentlessly toward the future.

And despite everything Parkinson’s has taken from him, Michael J. Fox is refusing to let it take the one thing he still insists on carrying:

Hope.