- Sejuani was the first champion released in 2012.
- Sejuani was first announced by Ezreal in one of his posts.
- Sejuani was the fourth champion mounted (the others are Nunu, Corki, and Rumble).
- She was also the second champion mounted on an animal (The other one being Nunu).
- Sejuani's title was formerly "The Winter's Claw," but has since been changed to "The Winter's Wrath."
- Sejuani is likely the anticipated female boar-themed champion, though many thought that the boar would be the champion herself rather than being the mount of the champion.
- Sejuani's boar is named Bristle, a reference to DotA's Bristleback/Rigwarl; a boar-like hero.
- Riot employees jokingly refer to Bristle as Kevin Tuggles.
- In Sejuani's Art spotlight, the artist names the layer that has the boar on it "Piggles". Screen capture of it.
- Sejuani is one of four champions to feature a Traditional skin that represents them as they were prior to a rework, along with Traditional Karma, Traditional Trundle and Traditional Lee Sin.
- Sejuani received a visual upgrade and a new Classic skin.
- Her previous classic skin was released in the store for two weeks before after her relaunch, before being retired. Players who owned Sejuani before her relaunch received Traditional Sejuani for free.
- Prior to it's appearance in the PBE, teaser/concept was released in the form of a sketch made by Quinn during her Journey Into the Freljord.
- On her new classic skin, her shield is replaced by a .
- The aim of her new classic skin is to tie in her visuals with her lore, which her chainmail bikini did not.
- She had a skin in development called Queen Sejuani but was later remade into her upcoming Classic Skin with her rework .
- There's an event between Ashe, Sejuani, and Lissandra that is similar to "The Hunt is On!", called, "Battle for Freljord". This makes it a 2nd event to happen in-game but not directly to the lore.
While similar, Sejuani and Bristle only drop one soul between them. This had led to a joke among the community that Sejuani has ginger hair in reference to the internet meme that gingers have no soul. 
It stils unknow if this is intentional, as Miss Fortune is a redhead and drops a soul.
- Sejuani's previous selection quote; "Winter is coming" is a reference to the motto of House Stark from the book series and the popular HBO program adaptation. It has also become a popular meme.
- Tradtional Sejuani shares a quote with Blackfrost Anivia; "To the bitter end."
- Sejuani's quote; "I will not hide behind another shield", might be a reference to her old model where she holds a shield.
- Sejuani shares a quote with Alistar: "Stampede!"
- Sejuani's horn on her helmet is on the right on her Classic Skin while it is on the left on her Traditional Skin, Sabretusk Sejuani Skin, and Darkrider Sejuani Skin .
- In the Chinese artwork for Darkrider Sejuani, she is wielding her weapon and shield in the opposite hands.
- Bear Cavalry Sejuani was made for the celebration of the launch of the Russian server.
- All summoners who play on the Russian server will receive this skin for free.
- The term "Bear Cavalry" may be a reference to an internet meme revolving around Russian bear-riders.
- It is rumored that Rengar stole the bear's left eye, since he lost his to Kha'zix. This would also explain why his left eye glows yellow, similar to the bears.
- According to the Journal of Justice, Sejuani is in direct conflict with Ashe, opposing Ashe's claim as the Queen of Freljord.
- Sejuani is distantly related to Ashe as they both descended from two of the three legendary princesses, who were sisters. Her ancestor being Serylda as stated by Greyor while Ashe's is Avarosa as stated by Lyte.
- Lissandra is also one of the three legendary princesses, effectively making her their ancient ancestor.
- Sejuani's gauntlet is the . An ancient, iceborn artifact that belonged to the iceborn's previous leader, Lissandra. It is currently unknown how she got hold of this though.
- Sejuani once fought with Olaf when he came to die in battle at the hands of the Winter's Claw. They fought till both of them fell to their knees. After being brought down by him, she recruited him as part of the Winter's Claw, promising him the glorious death he desired.
- Volibear allied himself with Sejuani to defeat the Frozen Watchers when they returned.
- Udyr allied with Sejuani for his mission to defeat The Ice Witch.