The athlete, 30, won the women’s 55-kilogram weightlifting competition in Tokyo, setting an Olympic record of 127kg in the clean and jerk event.
Diaz is from Zamboanga, in the south of the South-East Asian islands nation, and as she made history with her gold medal, a host of her most famous countrymen and women celebrated her win on social media.
Filipino-German model Pia Wurtzbach acknowledged the win on social media, celebrating "a strong and amazing woman".
"We are so proud of you," Wurtzbach wrote on Twitter.
Boxer and politician Manny Pacquiao took to Twitter to thank the athlete.
"Thank you, Hidilyn Diaz, for the first-ever Olympic Gold for the Philippines! We are so proud of you," he wrote.
Filipina actress and director Bela Padilla recognised Diaz's achievement, writing: "Thank you for carrying us all."
Television presenter, former volleyball player and activist Gretchen Ho is also in Tokyo, covering the Olympic Games. She tweeted about Diaz's achievement a number of times, most notably posting a photo of the athlete's blistered hands, writing: "Golden hands of @diaz_hidilyn."
Immediately after the win, Ho tweeted an image of Diaz in action, sharing the news with the world.
She later tweeted an image of Diaz reacting to her triumph. "What gold means," Ho wrote.
Ho has since interviewed Diaz for a TV special for the Filipino channel TV5.
Filipino singer Gary Valenciano retweeted a number of Ho's posts from Tokyo. Valenciano wrote: "You went for gold and you got it Hidilyn Diaz!"
He later said he was "speechless", describing Diaz as "outstanding".
Actress Janine Gutierrez celebrated Diaz's win by describing the champion as the "hero we need on SONA day", in reference to the State of the Nation Address, an address by the president of the Philippines, which is delivered on the fourth Monday of July annually. This year it coincided with Diaz's event.
American WWE wrestler Shotzi Blackheart, born Ashley Urbanski, and who is of Filipino and Polish descent, tweeted her "Pinay pride" following Diaz's medal win.
"Hidilyn Diaz is Philippines' first ever gold medallist!" Shotzi wrote, with a series of flag and colourful heart emojis.
Filipina senator Risa Hontiveros tweeted that Diaz "makes us proud", posting a photo of herself with the athlete.
Hong Kong TV host Richard Juan, who lives in the Philippines, wrote: "The fact that our first Olympic GOLD medallist, Hidilyn Diaz was born, raised and trained here in the Philippines just made it extra SWEET. Congratulations!"