MONTCLAIR, NJ – An interim chief executive officer (CEO) has been named for Hackensack Meridian Mountainside Medical Center, officials announced.

A search is underway to replace John Fromhold, who recently announced his retirement. Tim O’Brien, who had served as Mountainside chief operating officer (COO), will now serve as interim CEO. 

O’Brien has served as Mountainside’s COO since 2017 and leads the COVID-19 preparedness operations at the hospital. During his tenure, he led program development efforts in neurosciences with the addition of advanced neuroendovascular services.  He has implemented significant operational improvements to enhance quality and service to patients, and served as the executive lead for the successful implementation of the Epic electronic health records system.

Sign Up for Nutley Newsletter
Our newsletter delivers the local news that you can trust.

“Tim has a deep knowledge of Mountainside operations and a collaborative style that will make the leadership transition seamless,” said Matt Maxfield, president of Ardent Health’s Americas division. “Under Tim’s stewardship, we can conduct a thorough nationwide search for a permanent CEO.” 

O’Brien previously served as COO at North Suburban Medical Center in Thornton, Colorado and was the interim COO and assistant administrator at Westside Regional Medical Center in Plantation, Florida. He started his career as a strategic and operational business consultant for hospitals and other healthcare organizations. 

A fellow of the American College of Healthcare Executives, O’Brien earned a master of business administration from the Vanderbilt University Owen Graduate School of Management in Nashville, Tennessee and a bachelor of science in public health, health policy and administration from the University of North Carolina in Chapel Hill.

Stay informed, sign up for our FREE daily eNews. Like us on Facebook, follow us on Twitter @TAPintoNutley  and Instagram @TAPintoNutley  Questions? Email us at