SAN FRANCISCO — AxiCom has named Ketchum’s Lisa Sullivan head of the Americas, the latest in a string of leadership changes at the WPP tech specialty agency.

As president of the Americas, Sullivan will be responsible for overseeing AxiCom’s North America business, with a focus on expanding offerings and into new categories. She also is charged with spearheading expansion across Central and South America.

Sullivan most recently spent more than six years as partner and managing director of Ketchum’s tech practice. Prior to joining Ketchum, Sullivan was general manager of WE Communications’ San Francisco operation.

“With technology central to every business across every industry, Lisa’s wide-ranging expertise will be invaluable to our clients as they work to engage ever-expanding stakeholder bases,” said global CEO Matt Lackie, to whom Sullivan will report. “She is a world-class strategic counselor, innovative thinker and brand builder, as well as a trusted team leader and talent manager. I am excited for the great counsel she will deliver for our clients, for the growth opportunities she will bring to our business, and the energy and care she will bring to our people and culture.”

Sullivan, who formally assumes her new role Sept. 12, is joining AxiCom following the departures of two AxiCom North America senior leaders — Katie Huang Shin and Steve Kerns.

Huang Shin, formerly AxiCom’s North America president, left the firm in January, a move that coincided with the installation of Lackie as the firm’s new global CEO. She has since joined Big Valley Marketing as president.

In August, Kerns, then-AxiCom’s North America managing director, left the firm, also joining Big Valley Marketing as CMO.