Walt Disney was highly involved in planning the Walt Disney World resort complex and park, coming to Florida in person to survey the land, meeting with local officials and announcing the project to the media but not being able to see his vision come to life due to his death from cancer in 1966. After Walt's death, his brother Roy Disney took over the project. Walt Disney Productions began construction on Magic Kingdom and the entire resort in 1967. The park was built as a larger, improved version of Disneyland in California.

Magic Kingdom was built over a series of tunnels called utilidors, a portmanteau of utility and corridor, allowing employees (called "cast members") or VIP guests to move through the park out of sight.

Because of Florida's high water table, the tunnels could not be put underground, so they were built at the existing grade, meaning the park is built on the second story, giving the Magic Kingdom an elevation of 108 feet (33 m). The area around the utilidors was filled in with dirt removed from the Seven Seas Lagoon, which was being constructed at the same time. The utilidors were built in the initial construction and were not extended as the park expanded. The tunnels were intended to be designed into all subsequent Walt Disney World parks but were set aside mostly because of financial constraints.

Magic Kingdom Park opened as the first part of the Walt Disney World Resort on October 1, 1971, commencing concurrently with Disney's Contemporary Resort and Disney's Polynesian Village Resort. It opened with twenty-three attractions, three unique to the park and twenty replicas of attractions at Disneyland, split into six themed lands, five copies of those at Disneyland (Main Street, U.S.A., Adventureland, Frontierland, Fantasyland, and Tomorrowland) and the Magic Kingdom exclusive of Liberty Square, rather than the Disneyland New Orleans Square. The Walt Disney Company promised to increase this number with a combination of replicas and unique attractions. While there is no individual dedication to Magic Kingdom, the dedication by Roy O. Disney for the entire resort was placed within its gates.

The only land added to the original roster of lands in the park was Mickey's Toontown Fair. The land originally opened in 1988 as Mickey's Birthdayland to celebrate Mickey Mouse's 60th birthday. Later the land was renovated as Mickey's Starland and eventually to Mickey's Toontown Fair. The land was home to attractions such as Mickey's Country House, Minnie's Country House, The Barnstormer at Goofy's Wiseacre Farm, and Donald's Boat. It closed on February 12, 2011, to make way for the expansion of Fantasyland. The Walt Disney World Railroad station in Mickey's Toontown Fair, which opened with Mickey's Birthdayland in 1988, was closed for the duration of the construction. In 2012, the space where Mickey's Toontown Fair sat reopened as a part of Fantasyland, in a sub-section called the Storybook Circus, where an updated Dumbo the Flying Elephant attraction was relocated. The Barnstormer was retained and was re-themed to The Great Goofini.

Since opening day, Magic Kingdom has been closed temporarily because of nine hurricanes: Floyd, Charley, Frances, Jeanne, Wilma, Matthew, Irma, Ian, and Milton. The first non-hurricane related day the park has closed is on September 11, 2001, due to the terrorist attacks that day. Walt Disney World was closed from March 15, 2020, to July 11, 2020, due to the COVID-19 pandemic. In addition, there are four "phases" of park closure when Magic Kingdom exceeds capacity, ranging from restricted access for most guests (Phase 1) to full closure for everyone, even cast-members (Phase 4).

"Magic Kingdom" was often used as an unofficial nickname for Disneyland before Walt Disney World was built. The official tagline for Disneyland is "The Happiest Place On Earth", while the tagline for Magic Kingdom is "The Most Magical Place On Earth". Up until the early 1990s, Magic Kingdom was officially known as Walt Disney World Magic Kingdom, and was never printed without the Walt Disney World prefix. This purpose was to differentiate between the park and Disneyland in California. In 1994, to differentiate it from Disneyland, the park was officially renamed Magic Kingdom Park.

Alcoholic beverages had been prohibited from the park since its opening, but this policy has gradually changed. In 2012, the Be Our Guest Restaurant opened selling wine and beer for the first time. This was the only place in the park where alcohol was permitted until December 2014 when four additional restaurants began selling beer and wine including Cinderella's Royal Table, Liberty Tree Tavern, Tony's Town Square Restaurant, and the Jungle Navigation Co. Ltd. Skipper Canteen. And finally in 2018, the park officially became the second Magic Kingdom-style park to serve alcohol at all table service restaurants, after Disneyland Paris in 1993.

Early in 2024, a Disney executive confirmed that the park will expand with the addition of a 12-to-14-acre (4.9 to 5.7 ha) land located "beyond Big Thunder."