WASHINGTON — APCO Worldwide has acquired Chicago firm Gagen MacDonald, adding expertise in organizational change and employee engagement.

Gagen MacDonald, founded 25 years ago by Maril MacDonald, will operate as a wholly owned subsidiary of APCO. MacDonald will continue to lead the consultancy as CEO, as well as join APCO’s global leadership team and board of directors.

In announcing the acquisition, APCO said the addition of Gagen MacDonald’s expertise in transformation, employee engagement and internal culture builds out the suite of corporate advisory services the agency currently offers.

“The strengths and cultures of APCO and Gagen MacDonald are incredibly complementary, and we both have a strong focus on collaboration, empathy and client excellence,” said APCO founder and chairman Margery Kraus. “The demand for human-centered transformation is more important than ever before and our clients are asking us increasingly to help with these transformations and their implications on employee engagement, internal culture and connection to purpose, reputation and business performance. I could not think of a better firm than Gagen MacDonald to help bolster APCO’s capabilities to guide clients on their transformative journeys.”

APCO’s acquisition of Gagen MacDonald is the most recent step in a long relationship between the two firms, which have partnered informally in serving clients. Gagen MacDonald’s experts will collaborate with APCO teams around the world.

“Margery and I have been dreaming for decades about the significant impact we could create through blending our respective areas of expertise,” MacDonald said. “This new relationship gives us a broader collaborative platform and opens up a vast new world of ideas and solutions we can offer our clients as we help them navigate the world we know now and shape the world that is coming.”