Kirsty Coventry is also the youngest ever, and the first from Africa.
She hopes her election as the first female and African president of the International Olympic Committee - beating six male candidates - sends a "powerful signal".
The 41-year-old former swimmer, who won two Olympic gold medals, secured a majority of 49 of the 97 available votes in the first round of Thursday's election. Zimbabwe's sports minister Coventry will replace Thomas Bach - who has led the IOC since 2013 - on 23 June and be the youngest president in the organisation's 130-year history. Her first Olympics as president will be the Milan-Cortina Winter Games in February 2026.
"It's a really powerful signal. It's a signal that we're truly global and that we have evolved into an organisation that is truly open to diversity and we're going to continue walking that road in the next eight years," Coventry said.
Coventry, who already sits on the IOC executive board and was said to be Bach's preferred candidate, is the 10th person to hold the highest office in sport and will be in post for at least the next eight years.
Coventry has won seven of Zimbabwe's eight Olympic medals - including gold in the 200m backstroke at both the 2004 and 2008 Games.
"The young girl who first started swimming in Zimbabwe all those years ago could never have dreamed of this moment," said Coventry.