The song was a commercial success in South Korea, topping both the Gaon Digital Chart and the Billboard K-pop Hot 100.

In a StarNews article published on May 21, 2012, an official from YG Entertainment revealed that 2NE1 had recorded seven new songs produced by Teddy Park and planned to release a new Korean album in mid-June.

"[16] In an interview with Star News, CL elaborated on the song's musical direction, saying: "We have always tried to mix different genres, whether it be rock or acoustic or hip-hop.

[20] Conversely, Owen Myers of Popjustice praised the song's composition and ranked "I Love You" as the best K-pop single of 2012, writing that "it combines the best bits of pop into a rarefied cavalcade of amazingness".

[22] Jeff Benjamin of the same publication praised the song's musical style, saying "in the last 30 seconds, the cut flips on itself for an all-out, punky-party jam that only the most formidable of pop acts could successfully pull off".

[25] Upon the song's release, it topped all South Korean daily charts, including Melon and Mnet, and achieved an all-kill.

[30] During its debut week, the song reached the number two position on the Gaon Digital Chart, placing behind "Loving U" by Sistar.

[33] By the end of the year, "I Love You" sold over 2.7 million digital units in the country, and was ranked as the eleventh best-selling song on the year-end component download chart.

[38] The first teaser for the song's music video was released on July 1, 2012, which composed a clip of Dara and Minzy singing snippets of their verses.

[39] "Slowly transitioning from space-pop styling to a more glamorous affair," as Bradley Stern writes, the members pose and pout on beds while showing off unique and intricate nail designs and looks.

[4] The dance practice video for the song was uploaded to 2NE1's YouTube channel on July 10, 2012, which was recorded by YG Entertainment's founder Yang Hyun-suk.

[42] During the intro performance, CL rapped a verse from the then-unknown track "Falling in Love" in English with a parrot on her shoulder, which would be released as their next single exactly one year later.

[45] Following the Japanese release of "I Love You" on September 19, 2012, it was chosen as the official accompanying track for 2NE1's Maybelline New York endorsement campaign in Japan, which provided the theme song to one of the cosmetics company's newly launched mascara lines.