The anthem was composed a few days after the 1932 coup in the very similar tune to the national anthem of Poland, Poland Is Not Yet Lost, and was first broadcast in July 1932. The original lyrics were by Khun Wichitmatra.
In 1934, the Thai Government launched a competition for the official national anthem, both with music and lyrics. For the music, Jangwang Tua Patayakosol composed another tune in a more traditional style called "Phleng Maha Nimit" but the government selected Phra Jenduriyang's melody because it sounded more modern. After that, in the competition for the lyrics with Phra Jenduriyang's music, the original words by Khun Wichitmatra won the first prize and are still used as an official lyrics, however, with a minor edit and an additional version which was written by Chan Khamvilai and won the second prize.
In 1939, when the name of the country was changed from Siam to Thailand, a competition was launched to create new lyrics, with those by Luang Saranuprapan winning. Prime minister Phibunsongkhram ordered the anthem to be played every day at 8.00 and 18.00, and ordered the population to stand up to show respect for the nation. That law is still in force today.
Here is a video with one of three current English Translations: