The song received positive reviews from critics, who praised its composition and lyrics as well as Henderson's vocals.

[1] On 13 February 2014, a video was posted on YouTube of Henderson announcing that "When You Were Mine" would be available for pre-order on iTunes on Valentine's Day, with the song scheduled for release on 21 March 2014.

[11] Upon its release, "When You Were Mine" debuted and peaked at number five on the ARIA Singles Chart issue dated 17 March 2014.

Melissa Redman from Renowned for Sound gave the song four-and-a-half stars out of five and predicted it to be another hit for Henderson due to "its heartfelt lyrics and acoustic vibe.

"[7] Marcus Floyd from the same publication noted that the song has "a boyish sweet-heartedly sung verse and an addictive chorus.

"[6] Take 40 Australia wrote that "When You Were Mine" has "a very catchy hook" and noted that the song features "Henderson's fast becoming signature sound of folk infused and guitar heavy pop music" which resembles "Borrow My Heart".

"[6] The video begins with Henderson surrounded by vintage furniture in the back room of the record store he works at; he is seen sitting and playing an acoustic guitar while singing the song's lyrics directly at the camera.

The next scene shows Henderson writing a letter and he puts it in a red post box outside the store.

When Henderson is shown closing the store, a girl customer (played by Kendra Appleton)[25] runs up to him and he invites her inside.

After Henderson shows the girl around the store, they head upstairs onto the rooftop where they spend the night chatting and looking at a view of the city.