A question that needs to be answered is why: "Why is the Barong Tagalog the national garment of the Philippines?" The really quick answer is President Ramon Magsaysay. To give you the complete, long, detailed answer, I'd have to go through hundreds of years of Philippine history. As the famous Sweet Brown says: "Ain't nobody got time fo' dat." So, I'm going to attempt to give you something somewhere in the between while remaining brief enough to be a blog post. Here goes . . .
Contrary to the popular and mistaken belief that Spanish colonizers gave Filipinos the Barong Tagalog to wear as a way to oppress and control them, the barong actually has been worn in the Philippines long before the Spanish ever arrived. The earliest known barongs were worn by the Tagalog natives on the island of Luzon way back when the Philippines was known as Ma-i.
Over many generations and hundreds of years, the barong was worn by Filipino people of varying social ranks and classes, and it has evolved in its look, what it was made of and how it was worn, as influenced by people of India, Indonesia, Malaysia, China and Spain. Fast forward through the Spanish colonization, through war with the United States and American occupation, through World War II and we get to 1950s Philippines and President Ramon Magsaysay.
To set the backdrop, during the 1950s, the Philippines and the United States had just fought against a common enemy, Japan, in World War II, which ended in 1945. The Philippines and the United States enjoyed an allied relationship since then. Filipino people at the time heavily accepted American culture and American clothing; so much so that they favored clothing styles from the United States. Presidents of countries often inspire and even set the clothing culture of the people they govern. So, it is not surprising that Philippine presidents that served just prior to President Magsaysay wore suits and tuxedos much more often than barongs in public.
Enter President Ramon del Fierro Magsaysay, Sr., who served as president of the Philippines from the end of 1953 to 1957. Considered a true man of the people, President Magsaysay was the son of a blacksmith and a school teacher that worked his way through college as a chauffeur and after college as an auto mechanic and a shop superintendent. After serving his country in the military in World War II and working his way through various offices in Philippine government, Magsaysay was decisively elected president of the Philippines on November 10, 1953.
At his oath taking ceremony, President Magsaysay wore a Barong Tagalog, which was a first for any president of the Philippines. From there on, he regularly wore a barong to most official and personal functions, which was also a first for any Philippine president at the time, making the barong fashionable as business and formal attire.
President Magsaysay's administration was considered one of the cleanest and most corruption-free in modern Philippine history, and it is often cited as the Philippines' "golden years". Though Magsaysay did not get to finish his presidential term because he perished in a plane crash on March 17, 1957 at the age of 49. Two million people attended his state funeral, and since then, many have called him the "idol of the masses". Among his many other accomplishments, President Magsaysay was the beloved and popular president that made the Barong Tagalog popular and widely worn.
For the sake of being complete, I must mention that in 1975, President Marcos made it all official when he designated the Barong Tagalog as “the national attire” of the Philippines and issued a decree proclaiming Barong Tagalog Week as June 5th to 11th.
Everything I've mentioned, and things I have not mentioned, have all contributed to the barong becoming the national garment of the Philippines. But many give a large amount of that credit to President Magsaysay.
This is by no means a comprehensive history of the Philippines or the Barong Tagalog. I've skimmed over many important historical developments. But, I hope you get a good sense of the how and why. I invite you to research and look further into your Philippine history in much more detail.
The Barong Tagalog: The Philippines' National Wear by Visitacion R. de la Torre