The earliest case of the phrase was posted in a discussion on 4chan’s /v board on August 4th, 2012.
The phrase emerged as users were arguing about the notion of staying at home instead of partying on a Friday night.
“Smug anime face” rose from the conversation, as a user posted a GIF of Yozora Mikazuki from the anime series Haganai.
The phrase would start spreading online, initially on the /a board of 4chan, then anime related subs of Reddit, paired with images of anime characters having a smug grin on their faces.
By 2016, the popularity of the trope rose significantly, appearing in posts on Facebook as well as Tumblr.
On July 20th, 2020, the hardcore band “Smug Anime Face” released their debut album on Bandcamp, under the title Filthy Waters.