The phrase "Spin To Win!" originated from how easily some kills were obtained with Judgment. The most famous video about it is drawing of Garen spinning to Ievan Polkka by Loituma.
Although it doesn't benefit from ability power, his ultimate, Demacian Justice, deals magic damage.
His ultimate is mentioned in a famous Diablo II: Lord of Destruction mod, Median XL, in a form of a sacred unique long sword. The weapon is called Demacian Justice.
Garen is currently the only champion to have his IP price reduced twice.
Garen is one of the 8 champions who do not have a single skill that scales off ability power; along with Darius, Draven, Olaf, Riven, Talon, Vayne and Zed.
Garen's joke and his taunt were changed from the Test Realm to Release. The previous joke was "I know you're in that bush!"
Garen's second joke is a reference to the Men's Wearhouse commercials, which always end with the line, "You're gonna like the way you look. I Garen-tee it. Get it?"
In Garen's basic skin art he wears a full glove on his left hand and no glove on his right, while on his ingame model he wears fingerless gloves on both hands.
In his Dreadknight and Rugged skin arts he is holding his sword in his left hand, but in-game he holds it in his right hand.
Dreadknight Garen is most likely a reference to the class Death Knight from World of Warcraft. His gear closely resembles their gear and he has the typical Death Knight's glowing blue eyes.
Rugged Garen was originally called "Vagabond Garen", and may be based on Geralt from the book and game series, The Witcher.
Several of Garen's skins appear to be references to factions from the Warhammer 40,000 series
Sanguine Garen is possibly a homage to the Blood Angels of which their primarch (leader) is Sanguinius.
Garen and Katarina first fought during a war between Demacia and Noxus. Garen has fought with her ever since, whenever the opportunity presents itself.
Garen and Katarina were the ones who stopped the inter-city brawl in Kalamanda.
According to Blitzcrank's "Fleshling Compatibility Service," a dating service made by Blitzcrank, Katarina and Garen make a perfect couple, but are not officially together. Fans have since been joking about their relationship.
The sixth issue of the Journal of Justice states Garen's family name is Crownguard, and every member of his family has joined the Demacian armed forces. His father and mother, Marcus and Lilia, are officials of the legislative Demacian Council. His younger sister Lux joined the military when she was thirteen.
Garen is a childhood companion of Jarvan IV, the crown prince of Demacia.
When Jarvan was captured by Noxian forces, Garen led his Dauntless Vanguard through enemy lines and rescued Jarvan before he could be executed. He bisected Urgot The Headman's Prid in the process.
Garen once protected Katarina when she came to Demacia to protest about High Councilor Heywan Relivash's conspiracy in Kalamanda along with Jarvan IV