Bryden was born in New York Hospital and grew up in an artist loft on Atlantic Avenue in Brooklyn Heights. Her parents divorced when she was five and she lived primarily with her father, Lewis, a painter and sculptor until she was 12 years old. Bryden then moved in with her mother, Jane, a classical soprano and professor at Smith College in Western Massachusetts. Bryden graduated from Amherst Regional High School, and deferred going to college for a year to skydive on a drop zone in Arizona, study Italian and opera in Manhattan and eventually travel to Australia for three months of backpacking, where she bought her first guitar. A classically trained musician (she studied the cello for ten years), Bryden dreamed of becoming an opera singer before hearing Jimi Hendrix and Janis Joplin for the first time. Bryden attended Wellesley College where she graduated Magna Cum Laude with a degree in English Literature. It was during this time that she began performing her songs live in the Boston folk and rock clubs.
Bryden was living in Greenwich Village in New York during 9/11, an event that had a "profound" effect on her. The following year, she recorded an album in Nashville and toured the US to support the album. Disillusioned with the music business, she travelled to New Orleans to write a new album, inspired by the jazz, roots and blues influences of the Crescent city. Bryden began recording with producer John Hill, but after the project ran out of money they returned to New York with a half-finished album. Two weeks later, Hurricane Katrina hit New Orleans, displacing many of the musicians on the record and destroying much of the town.
Bryden began touring the UK and Ireland by self-booking her tours, playing up to 250 shows a year abroad, opening for artists such as the Counting Crows and KT Tunstall. After coming across a Milton Avery painting during an attic clear out (a gift from her father when she was still a baby), Bryden auctioned the piece and received a substantial amount for it. She then used the money to re-record her album, but this time around bringing on board Grammy-winning record producer David Kershenbaum.
The resulting album, What Does it Take, came out on 12 October 2009 on Cooking Vinyl in the UK and Ireland and enjoyed considerable critical success.
In 2008, following a chance meeting with a US Army colonel at SXSW in Austin, Texas, Bryden flew to Iraq to play for the Armed Forces. Her second tour there in 2009 was documented by Susan Cohn Rockefeller for her film Striking A Chord. The film is about the healing power of live music for combat-related stress, which can lead to Post Traumatic Stress Disorder (PTSD). Striking A Chord was sponsored by Nile Rodgers of the We Are Family Foundation.
Shake The Tree was recorded at Metrophonic Studios, outside London, in the summer of 2010. Bryden collaborated with British guitarist and songwriter Patrick Mascall, with whom she began writing songs that reflected their mutual admiration for the likes of Bruce Springsteen, Dolly Parton, Willie Nelson and Emmylou Harris. By the following autumn, they had amassed forty songs.
Bryden started recording a new album in 2011 at State of the Ark studio in London, owned by Terry Britten. The first single from Shake The Tree, "Buildings and Treetops", came out in June 2012 and the album was released on the 18th. The single was awarded A-list BBC Radio 2 rotation and was greatly supported by Smooth FM and UK regional radio. Following the success of the first single "Buildings & Treetops" (which was a top 20 airplay hit), "Sirens" was released on 10 September 2012, and spent three weeks on the BBC Radio 2 A-list. A poignant and soaring anthem inspired by Bryden's hometown of New York City, as well as her personal experience during the devastating aftermath of 9/11, "Sirens" was a song Bryden avoided writing for ten years. One day in August 2011, as the ten year anniversary of 9/11 approached, she began describing her experience to Mascall at Metrophonic Studios. By that afternoon, they had completed the song.
Following the release of "Sirens", Bryden was approached by Take That lead singer Gary Barlow, who asked her to join him as the support act for his UK tour from November to January 2013. During these few months, Bryden also supported Jools Holland for several of his UK dates, including a second performance at the Royal Albert Hall, the first with Gary Barlow earlier that month. Her 40 date string of gigs ended with a Nell Bryden headline tour in January 2013. Bryden released two further singles, "Shake The Tree" in January and "Echoes" in May 2013 with a further headlining tour from May to June of that year. The summer months saw her perform at a host of music festivals including V Festival. In September 2013, singer Cher recorded "Sirens" and released it as part of her album "Closer To The Truth".
Bryden released new record Wayfarer, a double CD that includes both the original and acoustic versions of the album, on 28 July 2014 through Absolute. The debut single from this album, "All You Had" was released at the end of 2013 and added to the BBC Radio 2 A-list. The second single and title track from the album, "Wayfarer" was added to A-list rotation at BBC Radio 2 and released on 4 August 2014.
In 2000, Bryden started her own record label, 157 Records which is a reference to the address of her childhood loft (on Atlantic Avenue in Brooklyn), and released four EPs. Bryden recorded her first full album Day For Night in 2005 and released it independently through the label. The album failed to generate industry interest. Bryden recorded her second album Second Time Around in New Orleans with John Hill and released it via 157 Records. After the lucrative sale of a Milton Avery painting, she re-worked the album with producer David Kershenbaum, adding new songs such as "Not Like Loving You" and "What Does It Take", plus several new remixes. The resulting album, renamed What Does It Take, was licensed to Cooking Vinyl in 2009 while Bryden retained ownership of her masters. She left Cooking Vinyl in 2011 and signed a deal with Warner Music/ADA to release Shake The Tree under her own revived label 157 Records.
In early 2011, during the recording of Shake The Tree, Bryden suddenly lost her hair from a stress-induced auto-immune condition called alopecia. She began to write songs that reflected the traumatic experience, but kept her condition from the public and wore a wig to continue performing. In June 2012, Bryden wrote a feature for the Mail On Sunday in the UK documenting her story. Several months later, following great feedback from the article, Bryden decided to begin performing without a wig, preferring instead to present herself as she is now.
Bryden married Alistair Moradi, a British man that she met while living in Notting Hill. They had a wedding celebration in Wiltshire, in June 2014 and had their first child, Tala Elizabeth, on December 3, 2014.
Nell presented her first radio show on BBC Radio 2 on the 25th August 2014. The show was an hour-long dedication to music born out of New York and featured some of the artists who had inspired Bryden as songwriter, as she grew up in the city.