The last act to their "school trilogy", the EP Skool Luv Affair, was released in January 2014 and topped the Gaon Album Chart, selling 100,000 copies in 2014 and over 250,000 copies overall. It also marked BTS' first appearance on Billboard's World Albums Chart, peaking at number three. The album was supported by the singles "Boy in Luv" (Korean: 상남자; Romanized: Sangnamja) and "Just One Day" (Korean: 하루만; Romanized: Haruman), which peaked at number 45 and number 149 in Korea, respectively. While Skool Luv Affair musically retained much of their hip-hop influences with the incorporation of R&B and hard rock, the album coincided with a thematic shift from dreams and happiness to love, focusing on school-age and youthful love. Following Skool Luv Affair's release, BTS made several appearances on Korean music shows and held their first fan meeting that March with an audience of 3,000 fans in Seoul. That July, BTS held their first concert in the United States in West Hollywood for free to an audience of 200 fans. In August, the group also made their first appearance at KCON in Los Angeles.
In August 2014, BTS released their first Korean studio album, Dark & Wild, which peaked at number two in Korea and sold over 200,000 copies total. It was supported by two singles: "Danger" and "War of Hormone" (Korean: 호르몬 전쟁; Romanized: Horeumon Jeonjaeng), which peaked at number 58 and number 173 in Korea, respectively. The album served as a narrative extension of the "school trilogy" and a transition into their next series. Musically, the album fused the grungy electric guitar sounds of rock within the framework of hip-hop and continued to expand their sound towards R&B. The central theme of the album's lyrics focused on expressing the sentiments of maturing, youthful desires, and impatience for romance. During production of the album, BTS recorded their single "Danger" in a makeshift studio in a garage in Los Angeles. Following several appearances on Korean music shows, BTS embarked on their first concert tour, 2014 BTS Live Trilogy Episode II: The Red Bullet, from October to December, held in various halls and theaters in six cities:
Seoul, Kobe, Tokyo, Manila, Singapore, and Bangkok.
Their first Japanese studio album, Wake Up (2014), released that December, peaked at number three on the weekly Oricon Albums Chart and sold 28,000 copies. Along with re-recorded Japanese versions of older songs, it also contained the original tracks "Wake Up" and "The Stars." In support of the album, BTS held their 1st Japan Tour 2015 Wake Up: Open Your Eyes in February 2015 to an audience of 25,000 fans in four cities. After ending their Japan tour, BTS held their second solo concert in Korea, BTS Live Trilogy Episode I: BTS Begins, in March to a crowd of 6,500 fans.