Kath and Cetera swap their usual instruments, with Kath on bass and Cetera on guitar. James William Guercio, Chicago's producer at the time, played guitar on the recording as well. Guercio appeared on stage with the band, playing acoustic guitar, when they performed the song on Dick Clark's New Year's Rockin' Eve to ring in 1975.
The instrumental track for the song had been recorded before Cetera realized it was too low for him to sing, so Kath performed the lead vocal instead.
The Beach Boys' collaboration with Chicago continued into 1975, where the two bands collaborated for the "Beachago" tour. "Wishing You Were Here," as well as other Chicago songs such as "Feelin' Stronger Every Day," were performed by the two bands together. The bands revived their collaboration for a second "Beachago" tour in 1989, during which they played this song. For the encore of one June 1989 performance, with Kath and Cetera no longer in the band, Beach Boys Mike Love and Carl sang Kath and Cetera's lead vocals, respectively.