Waddell began singing at the age of three in her home church, Truth Temple of Kannapolis, North Carolina. She, along with her brother and cousin, eventually became involved with the church's daily program on Charlotte TV station WAXN. In high school, she was a member of her school's advanced chorus group, and had the opportunity to perform with them at Carnegie Hall in New York. Waddell is also an alumna of Duke University's Brightleaf Music Workshop.

Waddell turned down a scholarship from Belmont University in Nashville, Tennessee, to pursue a full-time music career. She felt that God was calling her to concentrate on music instead of going to college. In 2004, she signed a management deal with Vertical Entertainment, and then signed a development deal with Word Records. Sparrow Records signed her in 2006, and her first album Say It was released on May 22, 2007. Britt Nicole was the opening act on the Winter Jam Tour with Sanctus Real, Hawk Nelson, Jeremy Camp, Steven Curtis Chapman, and Newsong.

Her song "Indestructible" was featured on the WOW Next 2007 compilation CD, and her summer festival plans include Creation East/West, Spirit West Coast Monterey/Del Mar, and Celebrate Freedom. She was featured on Christian hip-hop group GRITS' 2006 release, Redemption, on the song Right Back (credited as "Brittany Waddell".)

On May 22, 2007 she released her debut album Say It. It peaked at #40 on Billboard's Christian Albums

The debut single from Say It, "You", hit the Top 10 on the R&R chart. It was the 12th most played song on Christian Hit Radio stations in 2007, according to R&R magazine. It also peaked at #6 on Billboard's Hot Christian Songs, her highest charting song to date.

Britt's first music video, for the song "Believe", premiered on the Gospel Music Channel on September 22, 2007. The song was the 21st most-played song of 2008 on U.S. Contemporary Christian music radio stations according to R&R magazine's Christian CHR chart.

"Set the World On Fire" was the album's third single. The song peaked at #11 on Billboard's Hot Christian Songs.

Those who tuned into MTV’s latest hit teen reality show "Newport Harbor, The Real Orange County" Wednesday, September 5, heard the music of Sparrow Records artist, Britt Nicole. Her song, “Sunshine Girl” from her debut release Say It, was prominently featured during a key moment in the show.

In 2009, Britt Nicole released her new song "The Lost Get Found" to promote her second album by the same name. The song debuted on the Top 20 of Billboard Hot Christian Songs, entered as #20, and has since far peaked at # 8. It peaked at #1 on Christian radio. The music video for the song was released as a single on iTunes on November 17, 2009. The single also included a remix and karaoke version of the track.

The Lost Get Found was released on August 11, 2009 and peaked at #1 on Billboard's Christian Albums Chart and #62 on the Billboard 200. The same month, a music video for her song "Holiday" (from Say It) surfaced on the internet.