John N. Irwin III

John is the president and co-founder of Orchard Ultrasound, an ultrasound semiconductor innovation lab in California. He helped build the team and shape the product roadmap. In 2025, Orchard spun out MaxQ Medical, which is developing the first all-in-one ultrasound imaging and focused-ultrasound transducer catheter probe to treat benign prostate disease and prostate cancer.

He is also a lead director of a breakthrough liquid biopsy company.

Earlier in his career, John co-founded Hillside Capital Incorporated/Brookside International LLC in 1977 and later Brookside Capital Partners in 2001, where he helped build the firm’s early investment approach and its reputation as a long-term partner to operating businesses.

John has spent much of his career running and growing operating companies with significant global footprints. He has led businesses with extensive R&D in chemistry, biology and high-performance plastics, overseeing strategy for product development and international expansion. One of his early ventures was a chemical company producing dyes and intermediates for the pharmaceutical industry. He and his colleagues went on to build a semiconductor plastic encapsulants business out of an acquisition of an unwanted electrical plastics division of a publicly traded company in 1979; by 1984, the company had captured over 40% of the addressable U.S. market.

In the 1990s, John led a global food packaging company focused on cellulose, collagen and plastic materials with substantial manufacturing facilities in the U.S. and Europe. He and his team expanded the business by privatizing several collagen factories in Czechoslovakia through the country’s public voucher system, undertaking one of the first privatizations after the fall of the Iron Curtain. He also launched a joint venture with a Japanese chemical company to develop high-performance plastic food packaging. He subsequently directed a food flavoring company, overseeing operations and strategic positioning prior to its sale to Kerry Ingredients in 2001.

Alongside his work as an operator, John has co-founded or helped start several middle-market private equity and private credit firms that support growing companies, including BPI and the Wicks Group in the 1990s, Clearview Capital in 2000, Brookside Capital Partners in 2001, and Brookside Equity Partners in 2012. Three of these private equity firms became SEC registered investment advisers.

John and his colleagues have served on the boards of numerous portfolio companies, including PSS (medical billing), Azek (building products), Senior Care (senior day-care services), Performance Health (rehabilitation and physical-therapy products) and SelectQuote (senior medical and life insurance).

John has also served on the boards of venture-backed companies in wireless networking, pre-GPS satellite vehicle tracking, specialty and cyber insurance, and cybersecurity, working with the founding teams on go-to-market strategy.

John graduated from Princeton University.

John is the chair of the Achelis and Bodman Foundation and the Watson Foundation and serves as a trustee of the Wildlife Conservation Society.