Which Eagles song reached number one on the Billboard Hot 100 in 1979?

The Eagles song that reached number one on the Billboard Hot 100 in 1979 was “Heartache Tonight.” It was the lead single from The Long Run, released in September 1979, and became the band’s final US number-one single before their breakup.

The song was written by Glenn Frey, Don Henley, Bob Seger, and J. D. Souther. Frey and Souther had begun developing the idea, and Seger contributed to the writing; the finished recording combined the Eagles’ polished harmonies with a tougher, blues-influenced rock sound. Frey sang lead vocals, with Henley also prominent in the vocal arrangement.

“Heartache Tonight” topped the Hot 100 on November 10, 1979, and earned the Eagles a Grammy Award for Best Rock Vocal Performance by a Duo or Group. It is often mixed up with “The Long Run” and “I Can’t Tell You Why,” which were also successful singles from the same album, but both peaked at number eight rather than number one.