Jimmy Kimmel’s Son’s Heart Defect ‘Has Been a Nightmare’ for Him: ‘They Know That Life Is Precious’

Jimmy Kimmel and his wife, Molly McNearney, have been riding an emotional rollercoaster since the birth of their son, Billy.

The 7-year-old was born with a rare congenital heart defect called tetralogy of Fallot (TOF) with pulmonary atresia and underwent his first surgery when he was only three days old.

“Billy’s heart defect has been a nightmare for Jimmy,” a source spilled to a news outlet. “Jimmy’s been incredibly strong and hopeful, but also fearful.”

Despite the worries and stress that comes with Billy’s health problems, Kimmel and McNearney know that “life is precious” and “all that matters” to them is that their son is “okay.”

Source: @jimmykimmel/instagramBilly Kimmel was born with a serious heart defect.

As OK! previously reported, Billy just had his third open-heart surgery at Children’s Hospital Los Angeles in late May.

“We went into this experience with a lot of optimism and nearly as much fear and came out with a new valve inside a happy, healthy kid,” the 56-year-old late-night host wrote via social media after the successful procedure.

“Walking around this hospital, meeting parents at their most vulnerable, children in pain and the miracle workers who do everything in their considerable power to save them is a humbling experience,” he continued. “And Billy, you are the toughest (and funniest) 7-year-old we know.”

Weeks earlier, Kimmel also encouraged others to donate to the children’s hospital in honor of his son’s 7th birthday.

“Billy turns 7 today and is doing great thanks to the doctors, nurses, therapists and staff at @ChildrensLA & @CedarsSinai,” he penned at the time. “Billy is asking friends ‘to give $7 because I’m seven to help kids in the hospital.’”

During a recent appearance on Good Morning America, Billy’s heart surgeon Dr. Vaughn A. Starnes explained that the little boy’s condition totally took his parents “by surprise.”

“They thought Billy was going to be perfectly normal and was until two or three hours after delivery,” he shared. “That’s when the nurse noted that the child was somewhat blue and sounded the alarms.”

Dr. Starnes stated that Billy’s condition was particularly a “very severe form” and described the situation as “the most scary, terrifying thing that a parent goes through.”

Star magazine reported the source’s comments on Billy’s heart defect.

For many, Jimmy Kimmel is the face of late-night laughter, a comedian who never misses a chance to deliver biting satire or heartwarming monologues. But behind the bright lights of Jimmy Kimmel Live!, the beloved host has been shouldering a deeply personal and painful battle that has forever changed his outlook on life and fame: the congenital heart defect of his youngest son, Billy.

It all began in 2017, when Kimmel shared the emotional story with his audience just days after Billy was born. What should have been a moment of pure joy for Kimmel and his wife, Molly McNearney, turned into a nightmare within hours. Billy, who seemed healthy at birth, turned purple and struggled to breathe. Doctors discovered that he had a rare heart condition — tetralogy of Fallot with pulmonary atresia — which required immediate surgery to save his life.

Since then, Kimmel has spoken candidly about how watching his infant son endure multiple open-heart surgeries has been the most agonizing experience of his life. On his show, he often chokes up recalling the moment he handed over his tiny baby to surgeons, feeling helpless and terrified that he might not see him alive again. He has described the ordeal as a “nightmare no parent ever wants to face,” and the scars — both physical on Billy’s chest and emotional in Kimmel’s heart — remain constant reminders of how fragile life truly is.

This heartbreaking journey has also transformed Kimmel from a mere entertainer into a passionate advocate for affordable healthcare. His moving monologues calling for protection of the Affordable Care Act and coverage for pre-existing conditions were rooted not in politics, but in a father’s raw fear and love for his child. Many fans believe that these moments have cemented Kimmel as more than a comic — he’s become a voice for families who fight silent battles every day, often behind hospital doors.

Beyond the headlines, Kimmel’s personal life has shifted in profound ways. In interviews, he shares how Billy’s fight has made him and Molly cherish every mundane moment with their children. Simple things like bedtime stories, family dinners, or watching cartoons together now feel priceless. He says openly that this painful experience has taught him and his loved ones to see every day as a gift, and to never take for granted the moments they have together.

Recently, with Billy growing older and continuing to recover, Kimmel has admitted that the fear never fully disappears. While Billy is now a smiling, energetic little boy, he will still need more surgeries in the future to maintain his heart’s function. Each medical appointment, each unexpected fever, or each sign of trouble triggers a fresh wave of anxiety for the comedian and his wife.

Despite this, Kimmel makes it a point to keep his home filled with laughter. He often jokes about how resilient Billy is — calling him the bravest person he knows — and says his son’s courage inspires him to show up for work every day and find humor, even when life seems unbearably heavy.

Fans, too, have rallied around Kimmel’s family, sending countless messages of love and support whenever he mentions Billy on his show. It’s a testament to how deeply audiences connect with him, not just as a celebrity, but as a father who wears his heartbreak on his sleeve.

While Jimmy Kimmel might be known for his jabs at Hollywood scandals and political gaffes, his most powerful message remains deeply human: life is precious, health is fragile, and behind every smiling face on screen, there may be battles no one ever sees. Through Billy’s story, Kimmel reminds everyone that even in the darkest times, hope, resilience, and the love of family can keep us going — one heartbeat at a time.

As Kimmel himself has often said, he has learned to measure success not by ratings or accolades, but by waking up to see his son’s smile each morning. For him, no standing ovation or Emmy award could ever match the quiet miracle of hearing Billy laugh, run, and dream big for a future that once seemed heartbreakingly uncertain.