Few songs have proven as lucrative as “Margaritaville,” a modest 1977 hit by singer and songwriter Jimmy Buffett that became an anthem for an entire life philosophy. The track was the springboard for Buffett’s business empire—restaurants, apparel, kitchen appliances, and more—marketing the taking-it-easy message of its tropical print lyrics.

After just a few years of expanding that notion into other ventures, the “Parrot Heads” of Buffett’s fandom began to account for $40 million in annual revenue—and that was before the vacation resorts began popping up.

Kevork Djansezian/Getty Images

“Margaritaville,” which turned 40 this year, was never intended to inspire this kind of devotion. It was written after Buffett, as an aspiring musician toiling in Nashville, found himself in Key West, Florida, following a cancelled booking in Miami and marveling at the sea of tourists clogging the beaches.

Like the other songs on his album, Changes in Latitudes, Changes in Attitudes, it didn’t receive a lot of radio play. Instead, Buffett began to develop his following by opening up for The Eagles. Even at 30, Buffett was something less than hip—a flip-flopped performer with a genial stage presence that seemed to invite an easygoing vibe among crowds. “Margaritaville,” an anthem to that kind of breezy attitude, peaked at number eight on the Billboard charts in 1977. While that’s impressive for any single, its legacy would quickly evolve beyond the music industry's method for gauging success.

What Buffett realized as he continued to perform and tour throughout the early 1980s is that “Margaritaville” had the ability to sedate audiences. Like a hypnotist, the singer could immediately conjure a specific time and place that listeners wanted to revisit. The lyrics painted a scene of serenity that became a kind of existential vacation for Buffett's fans:

Nibblin' on sponge cake,
Watchin' the sun bake;
All of those tourists covered with oil.
Strummin' my six string on my front porch swing.
Smell those shrimp —
They're beginnin' to boil.

By 1985, Buffett was ready to capitalize on that goodwill. In Key West, he opened a Margaritaville store, which sold hats, shirts, and other ephemera to residents and tourists looking to broadcast their allegiance to his sand-in-toes fantasy. (A portion of the proceeds went to Save the Manatees, a nonprofit organization devoted to animal conservation.) The store also sold the Coconut Telegraph, a kind of propaganda newsletter about all things Buffett and his chill perspective.

When Buffett realized patrons were coming in expecting a bar or food—the song was named after a mixed drink, after all—he opened a cafe adjacent to the store in late 1987. The configuration was ideal, and through the 1990s, Buffett and business partner John Cohlan began erecting Margaritaville locations in Florida, New Orleans, and eventually Las Vegas and New York. All told, more than 21 million people visit a Buffett-inspired hospitality destination every year.

Kevork Djansezian/Getty Images

Margaritaville-branded tequila followed. So, too, did a line of retail foods like hummus, a book of short stories, massive resorts, a Sirius radio channel, and drink blenders. Buffett even wrote a 242-page script for a Margaritaville movie that he had hoped to film in the 1980s. It’s one of the very few Margaritaville projects that has yet to have come to fruition, but it might be hard for Buffett to complain much. In 2015, his entire empire took in $1.5 billion in sales.

As of late, Buffett has signed off on an Orlando resort due to open in 2018, offering “casual luxury” near the boundaries of Walt Disney World. (One in Hollywood, Florida, is already a hit, boasting a 93 percent occupancy rate.) Even for guests that aren’t particularly familiar with his music, “Jimmy Buffett” has become synonymous with comfort and relaxation just as surely as Walt Disney has with family entertainment. The association bodes well for a business that will eventually have to move beyond Buffett’s concert-going loyalists.

Not that he's looking to leave them behind. The 70-year-old Buffett is planning on a series of Margaritaville-themed retirement communities, with the first due to open in Daytona Beach in 2018. More than 10,000 Parrot Heads have already registered, eager to watch the sun set while idling in a frame of mind that Buffett has slowly but surely turned into a reality.