February 14, 2012, K.Will released his 3rd mini album I Need You two weeks after releasing a digital single of one of the songs from the mini album titled "I Hate Myself". On the same day, K.Will also unveiled a music video for "I Need You" on Starship Entertainment's official YouTube channel which features Sistar's Bora and actors Ji Chang Wook and Yeo Jin Gu. "I Need You" peaked at No. 2 on the Billboard K-Pop Hot 100, while "I Hate Myself" peaked at no. 6. The album marked the five-year anniversary of K.Will's debut as a singer-songwriter. His self-composed song, "I'll Be With You" is also included and is dedicated to all his fans who believed in him. He was also the co-writer the lyrics of "I'm Will." K.Will earned his first K-Chart award since his debut 6 years ago on KBS Music Bank for his track "I Need You." On October 7, Starship Entertainment revealed some photos of K.Will's recent photoshoot for his upcoming album. The album Third Album, Part 1 was released on October 11 along with the MV for "Please Don't...", the title track. Promotions for "Please Don't..." were the most successful in K.Will's career to date. The music video starred Seo In-guk, Sistar's Dasom, and Ahn Jae-hyun, and was praised for its originality. It was also notable for its twist ending involving Seo's character revealing he is actually in love with Ahn's. On February 14, 2013, Powerhouse Live (U.S.) presented K.Will in a Valentine's Day solo concert in the Orpheum Theatre in Los Angeles, California. He performed his hits, including "Please Don't...", "I Need You", "My Heart is Beating", and "Love 119". On April 3, K.Will released his new single, "Love Blossom." On October 19, K.Will released his new album, Will in Fall. The music video for the album's single, "You Don't Know Love", starring EXO rapper Chanyeol and South Korean model Lee Ho Jung, came out two days later, on October 21. On February 11, 2014, Mamamoo did a collaboration with K.Will with the single "Peppermint Chocolate" featuring Wheesung. On June 25, K.Will released his mini album, One Fine Day. The music video for the title track, "Day 1", starred Sistar's Soyou and Park Min-woo. On March 25, 2015, K.Will released his mini album, [Re:]. The music video for the title track, "Growing", starred Son Ho-jun and Park Ha-sun. On January 3, 2016, Starship