Hart Kail is the son of American actress Michelle Williams and theatre director Thomas Kail. He was born in 2020 and is the couple’s first child together. Hart is also the younger half-brother of Matilda Ledger, Michelle Williams’ daughter with the late actor Heath Ledger.
Michelle and Thomas keep their children away from the public spotlight. Because of this, only a small amount of information about Hart’s personal life has been shared publicly.
Hart Kail’s Profile Overview
| Detail | Information |
|---|---|
| Full name | Hart Kail |
| Birth year | 2020 |
| Reported birth month | June 2020 |
| Age | 6 years old as of 2026 |
| Nationality | American |
| Mother | Michelle Williams |
| Father | Thomas Kail |
| Older half-sister | Matilda Rose Ledger |
| Younger siblings | Two |
| Known for | Being Michelle Williams and Thomas Kail’s son |
Hart Kail Was Born in 2020
Hart Kail was born in 2020 during the COVID-19 pandemic. Some reports give his birth month as June, but his exact date of birth has not been publicly confirmed.
Michelle Williams’ pregnancy was reported in December 2019. In January 2020, she appeared with Thomas Kail at the Screen Actors Guild Awards while pregnant.
Williams later spoke about having a baby during the pandemic. She told Variety in 2022 that Hart’s arrival reminded her that life continued even during an uncertain period.
She explained that although the world was different from what the family had expected, Hart was able to enjoy discovering new things while growing up in a loving home.
Who Is Hart Kail’s Mother, Michelle Williams?
Hart’s mother, Michelle Ingrid Williams, is an American actress. She was born on September 9, 1980, in Kalispell, Montana.
Williams became widely known through the television series Dawson’s Creek. She later built a successful film career with roles in movies such as Brokeback Mountain, Blue Valentine, Manchester by the Sea, The Greatest Showman and The Fabelmans.
She also starred as Gwen Verdon in the television miniseries Fosse/Verdon. Her work on the series brought her major awards and also connected her professionally with Thomas Kail.
Before her relationship with Kail, Williams was in a relationship with Australian actor Heath Ledger. They had one daughter, Matilda Rose Ledger.
Ledger died in January 2008. Williams continued raising Matilda while largely protecting her from public attention.
Williams later married musician Phil Elverum in 2018. Their marriage ended in separation the following year.
Who Is Hart Kail’s Father, Thomas Kail?
Thomas Kail is an American theatre and television director. He is especially known for his work in musical theatre.
He directed the Broadway musical Hamilton, created by Lin-Manuel Miranda. His work on Hamilton earned him the Tony Award for Best Direction of a Musical.
Kail also worked on Fosse/Verdon, the television miniseries starring Michelle Williams. He served as a director and executive producer on the project.
Williams and Kail met through their work on the series. Their relationship later became public, and they became engaged in 2019.
The couple married in 2020.
Michelle Williams and Thomas Kail’s Marriage
Michelle Williams and Thomas Kail reportedly began dating after their previous marriages had ended.
Their engagement and Williams’ pregnancy were reported in December 2019. They married privately in 2020, with some reports placing their wedding in March.
Hart arrived later that year.
Williams and Kail rarely share details about their marriage or children publicly. They sometimes attend major entertainment events together, but their family life remains mostly private.
Hart Kail Has Three Siblings
Hart is one of Michelle Williams’ four children.
His oldest sibling is Matilda Rose Ledger. Williams then had Hart with Thomas Kail, followed by another child in 2022 and a daughter in 2025.
This makes Hart Michelle Williams’ second child overall and her first child with Thomas Kail.
Matilda Ledger Is Hart’s Older Half-Sister
Matilda Rose Ledger was born on October 28, 2005, in New York City. Her parents are Michelle Williams and the late Heath Ledger.
Hart and Matilda share the same mother but have different fathers.
Matilda was around 14 years old when Hart was born in 2020.
Williams has kept Matilda out of the spotlight for most of her childhood. She has explained that she wanted her daughter to have a normal routine and the freedom to be herself.
In November 2022, Williams said Matilda enjoyed classic Christmas movies and was excited to share them with the younger children.
Reports after the arrival of the family’s youngest child in 2025 also said Matilda was close to and caring toward her younger siblings.
Hart Has Two Younger Siblings
Michelle Williams and Thomas Kail welcomed another child in 2022. The couple was seen walking in New York City with a newborn in October of that year.
The child’s name and sex have not been publicly confirmed.
The family grew again in early 2025. Williams and Kail welcomed a baby girl through surrogacy.
Williams later confirmed the child’s arrival during an August 2025 appearance on Jimmy Kimmel Live!. She publicly thanked the surrogate, Christine, for helping them welcome their daughter.
The name of Hart’s youngest sister has not been publicly revealed.
Hart Kail and Heath Ledger
Heath Ledger was not Hart Kail’s father. Ledger was the father of Hart’s older half-sister, Matilda.
Ledger was an Australian actor known for movies including Brokeback Mountain and The Dark Knight. He and Michelle Williams met while working on Brokeback Mountain and later became a couple.
They welcomed Matilda in 2005 and separated in 2007.
Ledger died on January 22, 2008, years before Hart was born.
What Michelle Williams Has Said About Hart
Williams does not often discuss Hart publicly, but she has shared a few details about him.
In a 2022 interview with Variety, she discussed raising a baby during the COVID-19 pandemic. Williams said Hart experienced the joy of discovering the world despite the difficult circumstances surrounding his birth.
She also described raising a child as something that made her more committed to creating a better world.
Williams shared another small detail about Hart during a November 2022 appearance on Live with Kelly and Ryan.
At the time, Hart was interested in Christmas. He particularly liked Santa’s reindeer and was trying to learn their names.
Williams said his bedtime songs were also Christmas carols.
Hart Kail’s Education
Hart’s school has not been publicly confirmed.
Michelle Williams and Thomas Kail keep information about their children’s education private. There is no reliable public information naming a school attended by Hart.
Does Hart Kail Have a Career?
Hart does not have a known career or profession. He is still a child.
He is sometimes described online as a celebrity child because both of his parents work in the entertainment industry. There is no confirmed information suggesting that Hart has started acting or working professionally.
Hart Kail’s Net Worth
Hart Kail does not have a reliably reported personal net worth.
Some websites publish wealth estimates for celebrity children based on their parents’ careers. Such estimates should not be treated as Hart’s personal wealth.
His parents have successful careers in acting, theatre, film and television, but their money should not automatically be counted as Hart’s net worth.
Is Hart Kail on Social Media?
Hart does not have any known verified public social media accounts.
His parents have made an effort to protect their children’s privacy. Accounts using Hart’s name should therefore not be considered official unless confirmed by his family.
Hart Kail Lives a Private Life
Hart has made very few public appearances, and his parents do not regularly share photos or personal information about him.
This is similar to how Michelle Williams raised Matilda. Williams has spoken in the past about giving her children privacy and allowing them to grow up without constant public attention.
As a result, details such as Hart’s school, close friends, daily activities and most of his hobbies are not publicly known.
Things to Know About Hart Kail
- Hart Kail is the son of Michelle Williams and Thomas Kail.
- He was born in 2020.
- June 2020 is widely reported as his birth month, but his exact birthday has not been publicly confirmed.
- He was born during the COVID-19 pandemic.
- He is Michelle Williams’ second child.
- Hart is the first child Williams shares with Thomas Kail.
- His older half-sister is Matilda Rose Ledger.
- Matilda’s father was the late actor Heath Ledger.
- Hart has two younger siblings.
- His youngest sibling is a girl born through surrogacy in early 2025.
- Williams revealed that Hart enjoyed Christmas songs and Santa’s reindeer when he was young.
- His school has not been publicly disclosed.
- He has no known public career.
- He does not have a reliably confirmed personal net worth.
- No verified public social media account belonging to Hart is known.
- Michelle Williams and Thomas Kail keep most details about their children private.
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