McDonald most recently served as interim head of AT&T’s ad-tech unit Xandr following the unexpected departure of former Xandr CEO Brian Lesser in March—making McDonald the second top leader to exit the company this year.

Prior to taking on the temporary role as head of Xandr, McDonald served as chief marketing officer for the ad-tech company and then chief business officer. Before joining AT&T, McDonald was president of marketing automation software company PubMatic, and also held roles at Time Inc., Fortune|Money Group and CNET Networks. In 2018, he was honored as one of Adweek’s 50 Indispensable Media, Marketing and Tech Players.

“Kirk brings a unique view of the market in that he has experience in media, technology and marketing,” said Juhl in a statement. “We were looking for someone who had both the right experience in media and the capability to lead the region through transformational change. Not only did Kirk demonstrate he has both, but his vision for making advertising work better for people aligned perfectly with ours.”

At Xandr, executive vice president of product and business development Mike Welch will take over as the new head of the company. Before joining Xandr in 2017, Welch spent more than a decade at AT&T working in a variety of roles related to advertising, sales and operations.

“Kirk McDonald is a remarkable talent, and we are grateful for the leadership he has provided Xandr,” said a Xandr spokesperson. “We look forward to collaborating with Kirk in his new role.”

This latest change follows months of tumult at Xandr that goes well beyond the changes in top leadership. In April, AT&T made the decision to consolidate its ad sales teams for Xandr and WarnerMedia, appointing Gerhard Zeiler to oversee both. Just last week, WarnerMedia CEO Jason Kilar announced sweeping changes to the company’s corporate structure, putting streaming front and center.