According to the International Federation of the Phonographic Industry (IFPI), "7 Years" was the seventh best-selling song of 2016 worldwide with 10.4 million digital downloads and track-equivalent streams.

"[5] Regarding the band's prior failure to break into the international market, Forchhammer stated, "It's like my father died at exactly the right moment – and I know that's something I shouldn't say, but I just did!

It is accompanied by a mid-tempo piano line, a percussion backbeat, slideshow projector incorporations, and a synthesized string section.

Danish newspaper Jyllands-Posten critic Anders Houmøller Thomsen compared the song to the Beatles' "When I'm Sixty-Four": "'7 Years' bubbles with ignited storytelling about life's fast speed, when the daydreams of childhood and youth suddenly becomes replaced by retirement-melancholia.

"[9] However, Time magazine named "7 Years" one of the Top 10 Worst Songs of 2016, saying, "Good luck explaining the meteoric popularity of this (yes, catchy) chewy contemporary pop-rock ballad, which makes a listener yearn for the artistic integrity of a band like Maroon 5.

[12] The song stayed there for four non-consecutive weeks, being held off of the top spot by Rihanna and Drake's "Work" (the reverse happened in the UK) and Desiigner's "Panda".

[15] On 12 February 2016, "7 Years" peaked at number one on the UK Singles Chart, with combined weekly sales of 105,000 units (including 3.65 million streams).

[21] On the chart issue dated 11 April 2016, "7 Years" spent its eighth consecutive week at number one, becoming the longest-running number-one single by a Danish act.

He described the process as capturing a raw and spontaneous emotional flow, mentioning on Billboard that it took three and a half hours to write the entire song.

[28] Linkin' Bridge, an American musical group from Louisville, Kentucky, covered the song during the semi-finals of NBC's America's Got Talent season 11 on 14 September 2016.