The song was the Spoonful's third consecutive single to enter the top ten in the United States, and it was their best performing to that point, reaching number two.

The single's European release coincided with a British and Swedish promotional tour, leading the song to be the band's first major hit outside North America.

The following month, during a break from their busy touring schedule, the Spoonful recorded the song at Bell Sound Studios in New York City.

"Daydream" proved influential, especially among British musicians, directly inspiring the 1966 compositions "Good Day Sunshine" by the Beatles and "Sunny Afternoon" by the Kinks.

[2][3] The Spoonful generally enjoyed the experience but found the schedule physically exhausting, and Sebastian additionally missed his girlfriend, Loretta "Lorey" Kaye.

[13] Zal Yanovsky, the Spoonful's lead guitarist, later compared the song's melody to that of "Got a Date With an Angel", a 1934 hit by the American jazz musician Hal Kemp.

[16] The journalist Paul Williams similarly writes the song owes much to the jug band tradition,[17][18] adding that the lyrics, which describe a love-fueled bliss boosted by beautiful weather,[7] seem almost ad-libbed by Sebastian.

[16] The author James E. Perone also characterizes it as pop music,[19] and the critic Paul Nelson considers it, alongside the Spoonful's other singles, as being representative of folk rock.

[14] Sebastian sang and whistled,[14] and he played a harmonica contribution which he later said was derivative of Nino Tempo and April Stevens' 1963 hit "Deep Purple".

[42] To expand the band's popularity to an international audience, their management organized several concert and television appearances in England and Sweden for the end of April 1966.

[47] Paul Williams reviewed "Daydream" in the third issue of his American magazine Crawdaddy!, one of the earliest publications devoted to rock and roll criticism.

[49] Among British critics, Derek Johnson of New Musical Express described "Daydream" as both "tuneful and pleasantly hummable", but also "not very meaty and maybe a shade corny.

"[50] Reviewing the latest releases in Melody Maker's "Blind Date" column, the singer Dusty Springfield also described the song as "corny", but she used the term favorably.

[54] The simple arrangement of "Daydream" was out of step with contemporary pop music trends,[54] and it inspired numerous similar compositions from British musicians.

[57][58][nb 5] In an attempt to write a song in the same vein as "Daydream", Paul McCartney composed "Good Day Sunshine",[15][59] which the Beatles recorded in June during the sessions for Revolver.

[60] "Good Day Sunshine" uses no guitars, but like "Daydream" it features honky-tonk piano, a shuffling beat, applied dominants and similarly themed lyrics.