McCarthy was born on August 28, 1997 in London, Ontario, where she was raised. She is the daughter of Margarita De Antuñano, Director of the Canada-Mexico Cultural Exchange Centre and a Spanish teacher and Barry McCarthy a retired Vice-principal. Her mother is Mexican-Canadian and father of Canadian origin. McCarthy has Canadian and Mexican blood. She speaks fluent English, Spanish, and French. She discovered her passion for acting since she was a child. She is passionate about acting, dancing and modelling and to vigorously pursues "her call in life ,". as she refers Her grandmother Beatriz Carrillo said "Emilia is a born artist who acts and dances, I think she was born with this gift".
McCarthy took acting classes at "Armstrong Acting Studios", in Toronto. In an interview she declared:
"I was about seven and literally woke up one day and said, Mom, Dad, I want to be an actress"
Then in 2006 she landed her first role as Elle Fanning's photo double in the film Babel starring Brad Pitt and Cate Blanchet. The movie was directed by Oscar winner, Alejandro Gonzalez Iñarritu.
At 8, McCarthy had the opportunity to perform with Cate Blanchett and Gael García Bernal as daughter Cate, a role she shared with Elle Fanning, in the winning film Golden Globe: Babel.
In 2007, at the age of 9 McCarthy landed the role of Laura Westover for the TV movie: Booky & the Secret Santa. In 2009, at age 11, she was hired again to resume the role of Laura Westover in the movie Booky's Crush being the last film in the series.
McCarthy made a special appearance in the episode "All In" on the CW-Ranked Beauty & the Beast as Cena. The episode was released on October 25, 2012. In addition Emilia published a book with her father's help when she was only eight years old. The book is titled "Baby's Wish", Emilia got the idea of the book from a dream she had.
McCarthy has performed in several theatre productions like Hairspray and Tarantella Cabaret, also made stage appearances in works such as Aida and Seussical Jr.
McCarthy auditioned in Toronto for Eli Roth, director / producer of the series. In April, Netflix premiered the series Hemlock Grove of 13 episodes. Emilia appeared in 9 episodes as Alyssa Sworn in the series.
McCarthy was the star of the web series Unlikely Heroes and Kid's Town in 2013. That same year McCarthy landed the female lead role in the film Bunks, a film original Disney XD. Where Lauren plays a camp counselor, who wants the rules are followed by campers.
McCarthy was part of the main cast of the film Zapped, she plays Taylor Dean, the antagonist of Zendaya's character. The film premiered on June 27, 2014 in the United States and United Kingdom and America premiered on August 10, 2014.
The July 15, 2013 it was confirmed that McCarthy would be part of the cast of the film Maps to the Stars. She played the character of Kayla. Production began in July 2013. EOne introduced the film with his other films in state post-production in 2013 at the Toronto Film Festival. On April 14, 2014, the first preview of the film that was released. The film premiered at the 2014 Cannes Film Festival and the performances of the cast were praised.
McCarthy plays the role of Abby Ackerman in the new YTV series Max & Shred, which also will be transmitted by Nickelodeon. The series had a release date of October 6, 2014 in the United States.
McCarthy's main influences are Ryan Gosling and Rachel McAdams. In 2014, she said in an interview, "Ryan Gosling and Rachel McAdams are my inspiration . They were also born in London, Ontario. So if they can do it, why not me?". In another interview she stated, "I am a big fan of Rachel McAdams and Ryan Gosling, as they are both from London, Ontario, which is where I was born and raised. Rachel McAdams went to the same drama school as me. Not only that, but both are amazing actors and knowing that they came from the same place I came from, is crazy".
Emilia McCarthy is also known for being a writer. At the age of eight, along with her father, she published her book Baby's Wish. There is a copy of the book in the London, Ontario Central Library.
In 2014, McCarthy graduated from high school. From 2015, she begins attending Wilfrid Laurier University in Waterloo, Ontario, Canada in parallel with her actress career.