Jonathan C. Hamill

Jonathan Corwith Hamill, 87, passed away peacefully on September 23, 2026, in Barrington, Illinois.

Jon is survived by Nancy Hibbeler Hamill, his beloved wife of 67 years, and his daughters, Susan (Clayton) Simmers and Kimberly (Jay) Dietz. He was predeceased by his son, David Hamill.

Born and raised in Wayne, Illinois, Jon was the eldest child of Corwith "Corky" Hamill and Joan Birnie Byron Smith Hamill. He grew up alongside his two younger sisters, Nancy Winter and Elizabeth “Betsy” (James) Bramsen. Nancy passed away earlier this year.

Jon attended The Hotchkiss School in Lakeville, Connecticut, graduated from Yale University in 1960, and earned an MBA from Northwestern University's School of Management in 1962.

He began his career as an investment advisor at Stein Roe Investment Counsel and quickly established a reputation for thoughtful counsel, integrity, and disciplined investment management. In 1994, together with colleagues Ralph Segall and Alfred Bryant, he co-founded Segall, Bryant & Hamill, LLC, helping build one of Chicago's most respected investment management firms. Throughout his career, Jon valued the friendships he developed with clients as much as the professional relationships themselves.

A passionate traveler, Jon explored nearly every corner of the world alongside his family, approaching each destination with curiosity, enthusiasm, and an appreciation for different cultures and landscapes.

He was equally at home outdoors, particularly on the waters of northern Wisconsin. Fishing at Coleman Lake Club was one of his greatest joys, and he proudly served as the club's president for many years. His lifelong appreciation for the natural world shaped both his personal interests and his philanthropic commitments.

Following the example set by their parents, Jon and his sisters, Nancy and Betsy, carried forward the mission of the Hamill Family Foundation, supporting conservation, environmental, educational, and community organizations throughout the Chicago area and beyond. Jon served on the board of Openlands for more than two decades and was recognized as Honorary Director for his exceptional leadership and advocacy. Jon was awarded Trustee Emeritus status for his time on the Executive Board of the Illinois Chapter of The Nature Conservancy and was also a Life Governing Member of Brookfield Zoo, continuing a family legacy of support.

Jon and Nancy enjoyed many winters in Naples, Florida and used their time there to become involved with many Florida charities, such as Naples Botanical Garden, the Conservancy of Southwest Florida and Naples Zoo. Their interest and financial support brought them personal enjoyment while creating a meaningful and lasting impact on the Southwest Florida community.

Jon's dedication to civic life was equally enduring. He served as President of Barrington Hills Country Club, as a trustee of the Village of Barrington Hills, as Chairman of the Investment Committee of the Barrington Area Community Foundation, and as a trusted advisor to numerous charitable and community organizations.

Nothing brought him greater pride than his family. He was a devoted husband, father, grandfather, brother, uncle, cousin and friend. He especially treasured time spent with his grandchildren: Emily Hamill, Lachlan Simmers, Corwith Simmers, Parker Dietz, Cass Dietz, and Rider Dietz.

Jon will be remembered as a true gentleman whose intelligence, curiosity, quiet generosity, sense of humor, and kindness touched the lives of all who knew him. His legacy lives on through his family, his friendships, the organizations he strengthened, and the many people who benefited from his wise counsel.

A celebration of Jon's life will be held at a future date.

In lieu of flowers, please consider a memorial gift to Openlands (Openlands.org) or Brookfield Zoo (www.brookfieldzoo.org/donation).