Inspired by Defense of the Ancients, a custom map for Warcraft III, Riot's founders sought to develop a stand-alone game in the same genre.

In League's main mode, Summoner's Rift, a team wins by pushing through to the enemy base and destroying their "Nexus", a large structure located within.

However, negative and abusive in-game player behavior, criticized since the game's early days, persists despite Riot's attempts to fix the problem.

In 2019, League regularly peaked at eight million concurrent players, and its popularity has led to tie-ins such as music, comic books, short stories, and the animated series Arcane.

Domestic and international events have been broadcast on livestreaming websites such as Twitch, YouTube, Bilibili, and the cable television sports channel ESPN.

League of Legends is a multiplayer online battle arena (MOBA) game in which the player controls a character ("champion") with a set of unique abilities from an isometric perspective.

[14] Non-player characters known as minions are generated from each team's Nexus and advance towards the enemy base along three lanes guarded by turrets: top, middle, and bottom.

[39] Phillip Kollar of Polygon noted that Blizzard Entertainment supported Warcraft III with an expansion pack, then shifted their focus to other projects while the game still had players.

[55] Originally developed by Riot for their tactical shooter Valorant (2020), Vanguard requires access to the device's kernel, which some users saw as unnecessarily intrusive.

[71][72] One day after revealing a $430 "Hall of Fame" skin to honor the career of professional gamer Faker,[73] Riot announced layoffs at the company, impacting Ben Rosado—the cosmetic's designer—and eliciting further negative responses from players.

[75] In November 2024, the studio said they would streamline player rewards in an upcoming patch, describing the game's various progression tracks and currencies as "needlessly complex".

[78] In mid-January 2025, game director Andrei van Room said they had "screwed up", explaining that a designer forgot to include the "first win of the day" experience bonus in their calculations, causing unintended consequences.

[79] The developer partially reverted some of the changes, including halving the cost of purchasing a champion, and the return of "hextech chests"[80]—a loot box system introduced in 2016.

[83] Sociologist Matt Watson said the plot and setting were bereft of the political themes found in other role-playing games, and presented in reductive "good versus evil" terms.

[100][101] The variety offered by the champion roster was described by Steven Strom of PC Gamer as "fascinating";[102] Jackson pointed to "memorable" characters and abilities.

[101] While reviewers were pleased with the diverse array of play styles offered by champions and their abilities,[101][97][102] Strom thought that the female characters still resembled those in "horny Clash of Clans clones" in 2018.

GameSpot's Tyler Hicks wrote that new players would pick up League of Legends quicker than DotA and that the removal of randomness-based skills made the game more competitive.

[101] Strom said the game was fast-paced compared to Dota 2's "yawning" matches, but slower than those of Blizzard Entertainment's "intentionally accessible" MOBA Heroes of the Storm (2015).

[121][122][123] At the 39th Sports Emmy Awards in 2018, League of Legends won Outstanding Live Graphic Design for the 2017 world championship; as part of the pre-competition proceedings, Riot used augmented reality technology to have a computer-generated dragon fly across the stage.

According to Jeffrey Lin, the lead designer of social systems at Riot Games, the majority of negative behavior is committed by players "occasionally acting out".

[133] To that effect, Riot reworked the "Honor system" in 2017, allowing players to award teammates with virtual medals following games, for one of three positive attributes.

[135] Online viewership and in-person attendance for the game's esports events outperformed those of the National Basketball Association, the World Series, and the Stanley Cup in 2016.

[138] The company sells streaming rights to the game;[51] the North American league playoff is broadcast on cable television by sports network ESPN.

[154] The scene has attracted investment from businesspeople otherwise unassociated with esports, such as retired basketball player Rick Fox, who founded his own team.

[157][158] A stand-alone version of Teamfight Tactics was announced for mobile operating systems iOS and Android at the event and released in March 2020.

[171] After a two-year hiatus, in August 2020, Riot Games released "The Baddest", the pre-release single for All Out, the five-track debut EP from K/DA which followed in November that year.

[172] In 2019, Riot created a virtual hip hop group called True Damage,[173] featuring the champions Akali, Yasuo, Qiyana, Senna, and Ekko.

[175] In 2023, Riot formed Heartsteel, a virtual boy band, comprising the champions Aphelios, Ezreal, Kayn, K'Sante, Sett, and Yone.

[177][178] Shannon Liao of The Verge noted that the comic books were "a rare opportunity for Riot to showcase its years of lore that has often appeared as an afterthought".

[187] Ahead of season 2's premier, Variety reported that production and marketing costs for Arcane's 18 episodes exceeded $250 million, making it the most expensive animated series ever made.