COO Shay Segev will replace the outgoing executive, with the changes effective from 17 July.
Alexander has overseen rapid growth at GVC since 2007, most notably with M&A activity including its takeover of Ladbrokes Coral, which was completed in 2018.
Segev has been GVC COO since March 2016, having previously been the Chief Strategy Officer of Gala Coral.
Alexander said: “I have given 13 years to GVC and I now want to give some time to my family. I have enjoyed every minute of helping to grow GVC into the business that it is today, and am proud of all that has been achieved.
“We have the best people, brands and technology in our sector, and our joint venture in the US with MGM Resorts positions us very strongly for growth in that hugely exciting market.”
Segev said: “I am hugely honoured to have been given this opportunity by the Board to lead GVC into the next phase of its development.
“Kenny has been a fantastic colleague and leader during the four years I have worked with him.
“Thanks to his stewardship I am succeeding him at a time when the business is in robust financial health with an exceptional team and exciting opportunities ahead of it, especially in the US.
“Our strategy will continue to be focused on our industry-leading technology, brands, products, marketing capabilities and people, as well as being absolutely committed to making gambling as safe and enjoyable as possible for our customers around the world.”