Short answers, pulled from the story.
The half-elf first appeared as a player character race in the Greyhawk supplement to the original 1974 edition of Dungeons & Dragons. It was later included in the original Player's Handbook in 1978 and the Monster Manual in 1977.
Lead designer Jeremy Crawford stated that Wizards of the Coast was no longer comfortable with options that start with 'half', calling the construction "inherently racist." The 2024 Player's Handbook replaced half-elf and half-orc rules with a system where players select mechanical traits from one parent's race while choosing how their character visually appears.
A sample of characters created on D&D Beyond from the 15th of August to the 15th of September 2017 found 10,454 half-elf characters per 100,000, making the half-elf the third most created race. Only elves at 16,443 and humans at 25,248 ranked higher.
In a 2017 sample of D&D Beyond characters, the three most popular class combinations with the half-elf were bard at 1,808 characters, warlock at 1,401, and rogue at 1,325.
The khoravar is the name for half-elves in the Eberron campaign setting. They consider themselves a separate people from both humans and elves, breed true as a distinct species, and bear the dragonmarks of Storm and Detection. The setting sourcebook Eberron: Forge of the Artificer in 2025 introduced khoravar as a new species choice in fifth edition.
Multiple academics have argued that the half-elf in D&D is directly traceable to Tolkien's portrayal of elves. Gary Gygax initially denied the influence but by 2000 acknowledged that Tolkien's works had a "strong impact" on the development of Dungeons & Dragons. A 1977 cease-and-desist letter from Tolkien Enterprises also reflects how obvious the similarities were.