Talia Castellano was born on August 18, 1999, in Orlando, Florida, and grew up in and around central Florida with her mother, Desiree Castellano, and in New York City with her father, Marc Winthrop. She had three siblings: Kaitlyn, Jackson Winthrop, and Mattia Castellano. When she was seven years old, Castellano began experiencing fevers and abdominal pain. When an X-ray on February 14, 2007, showed unusual anatomical displacements in her chest, she was diagnosed with neuroblastoma, a rare pediatric cancer of the peripheral nervous system.

She underwent various types of therapies and treatmentsand was initially declared cancer-free, but relapsed three times in the next six years. During that time, she was diagnosed with myelodysplastic syndrome (previously known as preleukemia) and progressive neuroblastoma. There are no known treatments to tackle both cancers at the same time. Although she was given only months to live, a novel drug therapy provided her with an additional 11 months.

When first diagnosed, she bonded with a family friend, Tammy DeLaRosa, who was also a cancer survivor. DeLarosa taught her how to use makeup. On August 27, 2011, she uploaded her first makeup tutorial, "Crazy eyeliner" to YouTube, where it gained over 30,000 views. Castellano was known for battling aggressive cancer, and she was well aware of the reality of the situation, according to her mother. She has stated in videos that she was not afraid of dying, and that "when it's my turn to go, that will be my turn to go." When Castellano became aware that her cancer was terminal, she opted to sign hospital forms requesting only palliative care.

In September 2012, she appeared on "The Ellen DeGeneres Show," and was announced as a face for CoverGirl cosmetics. She subsequently appeared in CoverGirl magazine ads with her slogan "Makeup is my wig" She also collaborated with the Orlando-based BASE Camp Children's Cancer Foundation, a program to give support to children battling cancer in the central Florida area and to their families.

Talia died at the Arnold Palmer Hospital for Children in Orlando, Florida, on July 16, 2013, about a month before her 14th birthday, after spending the last three months of her life in palliative care. After years of grueling treatment with the disease metastasized, she declined any further proactive treatment. An announcement was made soon after the time of her death, on the Angels For Talia Facebook page.

At the time of her death, her channel had more than 750,000 subscribers and 45 million video views. As of November 2016, her YouTube channel has grown to more than 1,400,000 subscribers. After her death, her Instagram feed @taliajoy18 still manages to have over 1.3 million followers.

Since her death, it's been her mom, her sister, and her fans' goal to keep her legacy alive by completing everything on her bucket list that she didn't get to do. She left her hand and footprints on this world.

If there's one thing Talia taught me, it was just to keep swimming.