Singh was born and raised in the Scarborough district of Toronto, Ontario. Her parents, Malwinder Kaur and Sukhwinder Singh, emigrated from Hoshiarpur, Punjab, India and raised her as a Sikh. Her older sister Tina (born 1982) is also a YouTuber; she makes videos about her family life with her husband and their three sons. Singh has said she was a tomboy as a child. She attended Mary Shadd Public School during her elementary years, and in 2006, she graduated from Lester B. Pearson Collegiate Institute in Toronto, where she returned as an alumna to visit her old teachers. She was a member of Girl Guides of Canada and participated in their youth programs. In 2010, she graduated from York University in Toronto with a Bachelor of Arts in Psychology.

In October 2010, Singh started a YouTube channel under the pseudonym “IISuperwomanII”. She has explained that the name Superwoman was prompted by a childhood idea, making her believe she could do anything. Starting out, Singh had intended to go to graduate school as her parents had requested, but chose to make YouTube videos and decided that she would return to graduate school if her YouTube career did not progress.

In December 2011, Singh created a second channel called “SuperwomanVlogs”, now titled “Lilly Singh Vlogs”, where she chronicles her daily activities and includes behind the scenes footage from her videos. She used it as a second channel to upload videos until August 2014, when she began uploading vlogs. Singh appeared as a background dancer in the movies Speedy Singhs and Thank You in 2011.

In August 2013, Singh was featured alongside Jassi Sidhu in his Punjabi song Hipshaker. Singh rapped in the song Mauj Ki Malharein, which played in the Bollywood drama Gulaab Gang in August 2014. In July of the same year, she released a song titled #LEH in a collaboration with her friend, author and rapper Kanwer Singh, who is known by the pseudonym “Humble the Poet”. In 2014, Singh appeared in a small role in the Canadian production Dr. Cabbie.

In 2014, her channel ranked at #39 on New Media Rockstars Top 100 Channels. The same year, she was nominated for a Shorty Award and a Streamy Award.

She recorded and released another music video in February 2015 titled The Clean Up Anthem in collaboration with Canadian artist Sickick.

In March 2015, Singh began a world tour called “A Trip to Unicorn Island”, adapting her YouTube content and including singing, dancing, music performances, comedy, and her parent characters. Her tour covered India, Australia, Hong Kong, Singapore, Dubai, Canada, Trinidad and Tobago, the United Kingdom, and the United States. She documented the tour in her first feature movie, A Trip to Unicorn Island, which also describes how YouTube fame is affecting her life. The movie was released on February 10, 2016 on YouTube Red (now called YouTube Premium). She describes the film as being very “raw and genuine”.

In April 2015, Singh released a song about her hometown Toronto in collaboration with Humble the Poet titled #IVIVI (roman numerals for 416, Toronto’s area code). In September 2015, People magazine included Singh on their annual “Ones to Watch” list. Lilly received her first MTV Fandom Award, was nominated for two Teen Choice Awards, and won her first Streamy Award later that year.

In December 2015, she moved to Los Angeles to further her career.

In October 2016, she ranked 8th on Forbes’ list of World’s Top-Earning YouTube Stars of 2015. She was also featured in Fast Company Magazine as the 100 Most Creative People in Business. Variety magazine recognized her as one of their 10 Comics to Watch for 2016, and she was honored at the Just For Laughs Film Festival in Montreal. In July 2016, she won two Teen Choice Awards from her three nominations.

In 2016, she voiced miniature unicorns named Bubbles and Misty in the animated film Ice Age: Collision Course and played a cameo role in the movie Bad Moms.

In January 2017, she won a People’s Choice Award for “Favorite YouTube Star”. In September 2017, Singh won her fourth Streamy Award.

Her first book, How to Be a Bawse: A Guide to Conquering Life, was released on March 28, 2017. The book reached No. 1 on the New York Times bestseller list. She won the award for Best Non- Fiction at the 2017 Goodreads Choice Awards. Her 2017 world tour was centered around the book release and key concepts she discussed.

Singh was cast in HBO’s film adaptation of Fahrenheit 451 after recording an audition outside an Internet café in Melbourne, Australia. She was in the region to promote her book and rushed the audition at her agent’s urging around 2 a.m. in May 2017. She plays the character of Raven, “a tabloid blogger who works with the fire department to spread the ministry’s propaganda by broadcasting their book-burning raids to fans”.

In October 2017, she hosted SlutWalk, an initiative started by Amber Rose.

In November 2017, Lilly Singh was also chosen as an ambassador for Pantene shampoo and partnered with Calvin Klein. In 2018, Singh appeared in the music video for Maroon 5’s “Girls Like You” featuring Cardi B.

In 2017, Lilly Singh was announced as a UNICEF Goodwill Ambassador, to advocate for children’s rights. She has led a campaign called “GirlLove”, promoting girls to end girl-on-girl bullying. In July 2018, Lilly travelled to South Africa as a UNICEF Goodwill Ambassador to meet the students of elementary schools who spoke against bullying and classroom violence.

In 2018, Singh was to star in NBC pilot Bright Futures. The show was later cancelled by NBC and the pilot episode was left unaired.

On April 13, 2018, Singh announced that she had launched her own production company Unicorn Island Productions. The company is based in Los Angeles, California.

In March 2019, NBC announced that Singh would host a new late night talk show, A Little Late with Lilly Singh, which succeeded Last Call with Carson Daly following its series finale later in the year. The show premiered on September 16, 2019 to positive reviews by critics.

In August 2019, Singh dropped the name “Superwoman” in an Instagram post.

Singh garnered controversy for her remarks on turbans. During a visit to Jessica Alba’s home, Singh met Alba’s two young daughters who were both wearing twisted towels on their heads, to which Singh responded “They look like my Punjabi friends […]” On September 27, 2019, BBC reported that Singh had apologized for an on-air joke that compared turbans to bath towels, in which members of the Sikh religion, who wear turbans for spiritual reasons, were angered by her remarks on NBC, with the BBC remarking that “[Singh] has used her platform to often call out public figures who she says deserve to be “cancelled” for their offences.”

On October 19 2019, Singh was named one of Vogue India’s Woman of the Year.

Singh developed a strong connection with her Punjabi heritage during visits to India. She struggled with depression, and began making YouTube videos as a way of dealing with her feelings. As a young adult, she lived with her parents in Markham, Ontario. In February 2019, Singh came out as bisexual to the public via social media.

In July 2020, Singh announced that she and other celebrities were bringing a National Women’s Soccer League team to Los Angeles. The team is expected to play in 2022.