In January 2019, French producer Gesaffelstein (who previously worked with Tesfaye on My Dear Melancholy,) began teasing a new collaboration. On January 11, 2019, Tesfaye and Gesaffelstein released "Lost in the Fire", the second single off the latter's second studio album, Hyperion. On April 18, 2019, Tesfaye released "Power Is Power" alongside SZA and Travis Scott, a song part of a series of music inspired by the television show Game of Thrones, of which Tesfaye himself is a fan. On May 5, Tesfaye, SZA and Travis Scott released the music video for their Game of Thrones-inspired track. On August 30, 2019, during the Telluride Film Festival, Tesfaye made his debut cinematic appearance in the film Uncut Gems.
On November 24, 2019, "Blinding Lights", the expected lead single of his fourth studio album, was announced via a Mercedes-Benz commercial on German television. The next day, footage of a music video being shot in Fremont Street, Las Vegas surfaced. News outlets then began reporting that Tesfaye would follow up "Blinding Lights" with another single titled "Heartless". In promotion of the upcoming album, episode seven of the Weeknd's manager Cash's Memento Mori Beats 1 radio show was released on November 27, 2019. The single "Heartless" went on to debut at number 32 on the Billboard Hot 100 and later became his fourth number one single on the chart, the following week. The second single "Blinding Lights" went on to debut at number 11 on Billboard Hot 100 the same week "Heartless" topped it, fell to number 52 in its second week, and then after a long climb reached number one on the chart on the issue dated April 4, 2020. Tesfaye revealed the album's title, After Hours, and release date, March 20, 2020, on February 19, 2020, and released the album's title track as a promotional single simultaneously. On March 7, Tesfaye appeared on Saturday Night Live, performing "Blinding Lights" and the previously unreleased "Scared to Live". Subsequently, the album was released on March 20, 2020, containing the singles "Heartless", "Blinding Lights" and "In Your Eyes". The record debuted atop the US Billboard 200, earning 444,000 album-equivalent units of which 275,000 were in pure sales. Shortly after the album release, on March 29, 2020, Tesfaye announced the release of three more previously unreleased songs: "Nothing Compares", "Missed You" and "Final Lullaby". In the album's first charting week, Tesfaye became the first artist to lead the Billboard 200, Billboard Hot 100, Billboard Artist 100, Hot 100 Songwriters and Hot 100 Producers charts simultaneously. After Hours had a second consecutive week at number one on the Hot 100 Songwriters chart (April 2020), due to five entries on the latest Billboard Hot 100 (singles), all of which he co-wrote and co-produced. In April 2020, Tesfaye announced he would be co-writing and starring in an upcoming episode of American Dad!, which later premiered on May 4, 2020.
In April 2019, Tesfaye bought ownership in esports company OverActive Media Group, the owners of Splyce and Overwatch League team Toronto Defiant, and will serve as the company's global ambassador.
In April 2019, Tesfaye was sued by British trio William Smith, Brian Clover and Scott McCulloh who accused Tesfaye of plagiarizing their song "I Need to Love" in order to create his song "A Lonely Night". Smith, Clover, and McCulloh sought $150,000 from Tesfaye and Ahmed Balshe in lieu of copyright infringement. In November 2019, Tesfaye attempted to get the song-theft lawsuit dismissed which was denied by Judge Percy Anderson.