his death on social media, saying that his father had been battling cancer.

McDonald first came to renown as an original member of King Crimson, which was founded in January 1969. By July of that year, the band appeared with the Rolling Stones in a concert in Hyde Park, and released its debut album, In the Court of the Crimson King, that October. The album only went to No. 28 on the Billboard chart, but it was later hailed as a prog-rock landmark. The opening track, "21st Century Schizoid Man," featured McDonald blazing on his saxophone.

By that December, however, the original band had broken up, and McDonald had departed; he and a fellow King Crimson musician, drummer Michael Giles, formed a duo which released one album. By 1974, McDonald was back to appearing with King Crimson, but its founder, guitarist Robert Fripp, disbanded the group soon after.

McDonald (who played various reeds and winds, keyboards and guitar as well as singing and eventually producing) found work as a session musician. He appeared on T. Rex's 1971 album Electric Warrior and its breakout hit, "Bang a Gong (Get It On)."

In 1976, McDonald co-founded the band Foreigner with guitarist Mick Jones and singer Lou Gramm. Foreigner found huge commercial success: McDonald appeared on that band's first three albums, all of which went multi-platinum. McDonald was fired from Foreigner in 1980, however.

In more recent years, McDonald appeared with 21st Century Schizoid Band — a group composed of King Crimson alumni. His first solo album was 1999's Driver's Eyes, and in 2017, he formed a new band, Honey West, which included his son Maxwell.