BEFORE TARZAN was swimming his way to American gold medals, there was Duke.

Before fellow Olympian Jim Thorpe was similarly being cast as a tribal chief in Hollywood, there was Duke.

And right before the current American president was born in Honolulu, elected as that area’s sheriff for the final time was Duke.

Duke Kahanamoku, born on this day in 1890, is one of the greatest U.S. athletes many Americans have never heard of. And fortunately for his legacy, today Duke — before even Thorpe and Olympic swimmer-turned-“Tarzan the Ape Man” actor Johnny Weissmuller — is being celebrated with a Google Doodle.

It’s a wonderful nod to (and swell of recognition for) the great man. If he had he been born a century later, his name might be as popularly known as Michael Phelps, Kelly Slater or Laird Hamilton.

The farther you get from the beach, the less likely it is that you hear the name Duke Kahanamoku. But when you move close to breaking waves (as my family did, to San Diego, when I was a boy), the more often you surely will hear references to “the Duke,” the father of modern surfing.

“Out of the water, I am nothing,” the Duke resonantly said before he fully became recognized as the “ambassador of Aloha” and Hawaiian culture. Hawaii celebrates Duke as a favorite son who was indeed quite something as a ceremonial envoy on land, as well. But when you have achieved such greatness in the pool and in the pipeline, it should also be underscored that, to invert that quote: In the water, he was everything.

In 1912, for instance, Duke was the marine version of Thorpe (a master on the field and track) at the Stockholm Olympics. The two men, both of whom were about 6 feet, stood particularly tall at those Games as multiple medalists. While Thorpe was winning the pentathlon and decathlon, “the Big Kahuna” was winning swimming gold in the 100-meter freestyle and silver in the 4×200 free.

Duke, who was called “the king of all swimmers,” would go on to be a double gold medalist in those two events at the 1920 Antwerp Games. Four years later, Duke would medal for a third time (silver) in the 100 free, beating his brother, bronze medalist Samuel Kahanamoku, in the event won by his pal Weissmuller (the future Hollywood Tarzan) at the Paris Games. Duke ended his Olympic career in his 40s, when he was an alternate for the U.S. water polo team.

Duke was the first athlete inducted into the Halls of Fame for both swimming and surfing. The swimming exhibitions he gave, buoyed by his Olympic fame, provided him with opportunities to popularize surfing from the California coast to the waters off Australia, where a 1914 trip helped the sport take hold Down Under. Wherever he paddled his 16-foot wood longboard around the world, he was also proudly peddling surfing’s greatness.

(Duke’s California fame also grew in 1925, when — in what the Honolulu Star-Bulletin called a “superhuman” rescue — he used his surfboard to help save a dozen stranded fishermen during the vessel Thelma’s fatal wreck off the coast of Newport Beach.)

Shortly after the Paris Games, Duke also became a Hollywood actor, sometimes (like Thorpe) playing tribal characters; three decades later, in the Oscar-nominated 1955 war film “Mister Roberts,” he played a “native chief,” still fit of body and regal of bearing.

Duke himself was a military police officer during World War II, and sheriff of Honolulu till 1961 (the year that Obama was born there). In the ’60s, after having helped push for Hawaii’s 1959 statehood, he portrayed himself in surfing documentaries and had a stake in Duke’s, the Waikiki club that was home to Don Ho and his band.

Duke Paoa Kahinu Mokoe Hulikohola Kahanamoku died in 1968, in Hawaii, as the island state’s ambassador.

“Despite his charisma on the screen and two decades of Olympic triumphs, it is perhaps for moments like these [his rescue heroics off Newport Beach] — for his character, for his ease in the water, his deep and unending love of Hawaii and her oceans — that Duke Kahanamoku is remembered most,” writes Google, in celebrating the great man’s 125th birthday with artist Matt Cruickshank’s tropical, longboarding Doodle.

Long live the Duke, the ambassador of Aloha.