On Wednesday, the septet held an online press conference to react to the news.
"To be honest, BTS reaching No.1 on the Hot 100 -- we never imagined it," said band member J-Hope. "It still feels like a dream. I don't know if this is reality. I'm still shaking, I'm still excited."
Their feat surpasses Psy's 2012 megahit "Gangnam Style," which made it to No. 2 on the chart, and bests BTS' own high mark of No. 4 with their March single "On."
The Billboard Hot 100 blends U.S. streaming, radio airplay and sales data across all genres.
Band member Jimin said the news brought him to tears and delivered a sense of satisfaction for the years of hard work the group has put in since their debut in 2013.
"It was at 4 a.m. that I heard the news and I was basically crying until I fell asleep at 7 a.m.," he said. "It felt like an acknowledgment for all the things that we have been doing. Being able to join together and do this in such difficult times for everybody and being lauded for this accomplishment made us really happy and made me cry."
Other members of the boy band also reflected Wednesday on the journey that has brought them to this point.
"I didn't think BTS would be in the limelight with such a global audience," V said. "We all came to Seoul from the provinces. We had a very small practice studio in the basement. It was just the seven of us practicing together and working together. Those memories are still very fresh in my mind."
He said that looking back on the group's humble beginnings "really amplifies the joy that I have now."
The celebratory mood for BTS' accomplishment was shared by many in their home country, including South Korean President Moon Jae-in, who called their achievement "truly amazing."
"It is a splendid feat that further raises pride in K-pop," he said in a statement released Tuesday.
Moon added that the rise of the cheery disco-pop track to the top of the chart was "all the more meaningful as it has been composed to give a message of comfort and hope to people around the world who are struggling with COVID-19."
BTS is no stranger to the top of the American music charts, reaching No. 1 on the Billboard 200 album rankings four times. But the Hot 100 represents a new level of widespread appeal for the K-pop act, as it doesn't rely solely on album sales by diehard fans but also streams and radio play.
"No. 1 on the Hot 100 chart is not something you can achieve with fan support only," said RM, the band's leader. "It requires exposure and acceptance by the general public."
RM said he thought several factors contributed to the song's success in the U.S. market, including the fact that "Dynamite" is the first BTS track with lyrics entirely in English. He also pointed to the song's carefree spirit and upbeat message.
"It's easy to sing along with or hum along with," RM said. "And it doesn't have a macro-level message. Rather, sometimes the simpler message is the message that really gets across."
BTS will be busy continuing to promote the song in the U.S. market in the coming weeks, with performances lined up on Today on Sept. 10 and on America's Got Talent on Sept. 16.
On the heels of their latest success, group member Suga on Wednesday identified the next target in the band's sights: a solo performance at the Grammys.
"We went to the Grammys at the beginning of the year and did a collaborative performance" with rapper Lil Nas X, he said. "Now I would like to do a single performance with just BTS on the Grammys stage. It would be great to receive an award, but that's not going to become a reality just because we want it...so for now, just getting to perform on the Grammy award stage is our goal."