The record features songwriting contributions from various regional and international musicians, including Miriam and Olivia Nervo, SM composer Kenzie, and Kim Tae-sung.

"I wanted to do music that puts the vocals up front... relaxing my shoulders a bit.

The Korea Times noted that the record served as "a departure from the sleek, fast-paced and beat-heavy dance music she has become synonymous with", particularly from her previous albums BoA (2009), Identity (2010) and Hurricane Venus (2010).

BoA elaborated that the creative process behind the record was to produce a relaxing and "comforting" album that could resonate with the general public, even if they were not necessarily fans of her.

She acknowledged that even though electronic music styles remained trendy at the time, her personal preference for Only One nonetheless leaned towards a more "relaxed" and easygoing aesthetic.

[8] It stayed in the top of the Gaon charts for weeks, and has sold about 2 million singles as of October.