The single was certified platinum by the Recording Industry Association of Japan in April 2002 for shipments of over 400,000 copies.

"A Day in Our Life" was used as the theme song for the television series Kisarazu Cat's Eye starring member Sho Sakurai.

[1] The song was released as a CD single on 6 February 2002, through the group's new record label J Storm.

[1] "A Day in Our Life" debuted at number one on the Oricon Singles Chart, selling 226,000 copies in its first week.

[3][4] It charted for eleven weeks and went on to sell over 378,000 copies, making it the 21st best-selling single of that year in Japan.