Nami Tamaki was born on June 1, 1988 in Wakayama, Japan. She began her career after being selected from thousands of applicants at an audition for Sony Music Japan, where she performed covers of Destiny's Child and Core of Soul. Her background in dance, which she started studying in 1999, became a defining element of her stage performance style.

She made her major debut in 2003 at the age of fourteen with the single Believe, which was used as an opening theme for the anime series Mobile Suit Gundam Seed. The song was a commercial success, reaching number six on the Oricon charts, and was followed by Realize, the fourth opening theme for the same series, which peaked at number three. Her third single of 2003, Prayer, continued her early momentum. For her work in this period, she was named New Artist of the Year at the 18th Japan Gold Disc Award.

Tamaki's connection to the Gundam franchise deepened in 2004 with the release of Reason, the first ending theme for Mobile Suit Gundam Seed Destiny. This single became her highest-charting release, reaching number two on the Oricon charts. She later contributed Result to the Mobile Suit Gundam Seed Destiny Special Edition compilations. Her debut album, Greeting, was released in February 2004 and was certified Gold. Her second album, Make Progress, released in 2005, became her first number-one album on the Oricon charts, followed by her third album Speciality, which also reached number one in 2006.

Throughout her career, Tamaki has provided music for numerous other anime series and video games. She performed Brightdown as an opening theme for D.Gray-man and Sanctuary for the series Kiba. Her song Fortune was the main theme for the PlayStation 2 role-playing game Radiata Stories, and she also made a cameo appearance in the Japanese version of the game. Additional video game contributions include CASTAWAY for Super Robot Wars J and Negai Hoshi for the Wii role-playing game Arc Rise Fantasia. Her sixteenth single, Give Me Up, was used as a theme song for the anime Yatterman.

After four albums with Sony Music Japan, including Don't Stay which featured songs from her D.Gray-man tie-in, Tamaki transferred to Universal Music Japan in 2008. Under the Universal-J label, she adopted the stage name nami and released the album Step in 2010, followed by Ready in 2011. She later transferred to Teichiku Records, a sub-label of Victor Entertainment, where she released singles including Lady Mind and Paradise, produced by Shinichi Osawa. In 2013, she released the single Real, which included a remake of her debut song Believe to commemorate the tenth anniversary of her career.

Her musical identity blends J-pop with techno-pop and rock elements, supported by her energetic dance performances. She has been recognized for her significant commercial tie-ins with the anime and gaming industry, becoming known for her contributions to the Gundam Seed franchise. In addition to her music career, she has performed in stage musicals, including Japanese productions of Sweet Charity and High School Musical, and appeared in the live-action film Lovely Complex. Her first greatest hits album, Graduation: Singles, was released in November 2006, marking her high school graduation. After a period addressing health issues related to sinusitis and vocal nodules, she continued to release music, including the album Singularity in March 2024.