To help promote the album, Kumi held a special event at Shibuya Station, where fans would replicate the dress she wore on the album's cover. Winners received either a signed copy of the album, or Kumi's first concert DVD, Secret First Class Limited Live.
The album was released in both 2CD and 2CD+DVD, each with different cover art. Limited editions contained the bonus track, the meaning of peace, which was previously released on Kumi's single love across the ocean. Unlike the version released for the Song Nation project Kumi performed with Korean singer-songwriter BoA, this version was not a ballad and, instead, was a dance pop track.
Upon its release, the album received generally positive reviews from both critics and fans, with many praised Kumi's vocals and maturity as her music career progressed.
Best ~first things~ is Japanese singer-songwriter Kumi Koda's first compilation album and contained all of her singles from Take Back (2000) to Promise/Star (2005). The three singles leading up to the album's release were Butterfly, flower and the aforementioned Promise/Star. The album did contain one new track: the first song No Tricks (styled as NO TRICKS), which received a remix seven years later on her 2012 album Beach Mix.
Best ~first things~ became Kumi's first album to chart at #1 on the Oricon Weekly charts and was her longest charting album, remaining on the charts for 124 weeks – over two years. The album also became one of her highest selling albums, having sold nearly two million copies as reported in 2007.