The 57-year-old MacKay grew up in Santa Fe and began his career at the opera company there following his graduation from the University of Minnesota. Over the course of ten years, he graduated from Opera Orchestra member and orchestra assistant to box office manager to business manager. In 1978, he went to Charleston to serve as director of finance and administration with Spoleto Festival USA; then, in 1984, Gaddes recruited him to Opera Theatre of St. Louis (OTSL), where MacKay became general director the following year.

In his 23 years at the helm of the company, MacKay led OTSL to become one of America's top seasonal opera companies, admired internationally for its programming mix of familiar and unusual works and the intimacy and high quality of its productions. In addition, the OTSL endowment grew from $682,000 to $20 million during his tenure.

Gaddes, who gave an indefinite date for his retirement when he submitted his resignation earlier this year, will remain in office until MacKay's tenure begins on October 1, 2008 (just after next summer's season, which Gaddes has already largely planned). Both men will be working with a new chief conductor, Edo de Waart, who was appointed earlier this year.