Grimmie joined YouTube in February 2009 under the username zeldaxlove64. In July of that year, the then-15-year-old singer performed a cover of Miley Cyrus' "Don't Wanna Be Torn" from Hannah Montana. Today, the video has more than 1.2 million views.
After Gomez's mom Mandy Teefey saw Grimmie's cover of "My Heart Will Go On," she asked her husband Brian Teefey to find her, per Entertainment Weekly. Gomez's stepfather became Grimmie's manager in 2010.
In 2010, Grimmie teamed up with YouTube star Sam Tsui to perform a cover of Nelly's "Just a Dream." The song went viral and has nearly 149 million views to date.
In 2011, Grimmie won the My YouTube competition—and she had some tough competitors. According to Billboard, the young star beat out Justin Bieber, Gomez and Rihanna. The competition helped launch her into YouTube stardom.
Later that year, Grimmie went on DigiTour—a tour that connects social media stars to their fans. According to JustJared, she also opened for Gomez, the Jonas Brothers and Allstar Weekend at the 2011 Concert for Hope. She would later open for Gomez at her band the Scene for their We Own the Night Tour and her solo Star Dance Tour.
2011 was clearly a big year for Grimmie. That same year she debuted her first EP Find Me.
In 2011, Grimmie attended the American Music Awards, where she won the Best Female New Media award.
In 2012, Grimmie appeared on ABC's Dancing With the Stars. While she didn't dance, she played the piano and sang David Guetta's "Titanium." Her YouTube cover of the song has more than 7.5 million views to date. That same year, she starred in Disney.com's web show Power Up: with Christina Grimmie.
In 2013, Grimmie released her studio album With Love.
Grimmie appeared on the sixth season of The Voice. After she performed "Wrecking Ball" for the blind auditions, all four judges (Adam Levine, Blake Shelton, Usher and Shakira) offered to be her coach. She ended up picking Levine. She made it to the finals and won third place. Host Carson Daly later said he was "shocked" she didn't win.
After The Voice, Grimmie signed a record deal with Island Records but was later dropped. In 2015, she competed in the Macy's iHeartRadio Rising Star competition and won. As the winner, she got to perform at the iHeartRadio Music Festival, where she performed her original songs "Shrug," "Cliché," and "Must Be Love."
In 2016, Grimmie released her second EP Side A. Her family released her follow-up album, Side B, after her death.
Grimmie starred in the 2016 film The Matchbreaker along with Wesley Elder.
Grimmie died June 10, 2016 after a man shot her inside the Orlando Plaza Live Theater in Orlando, Fla. Grimmie had performed there earlier in the night with the pop rock band Before You Exit and was signing autographs for fans when the man opened fire. Levine paid for her funeral.
In 2017, Grimmie's family helped launch the Christina Grimmie Foundation, a nonprofit that supports individuals and families affected by gun violence or breast cancer. Grimmie's parents Tina Grimmie and Bud Grimmie and her brother Marcus Grimmie celebrated the launch in New Jersey.