Keith Alwyn Brunell, who spent his career teaching mathematics at Concord-Carlisle High School and coached the boys cross country team for 18 years, died June 29 at The Highlands Assisted Living in Topsham, Maine. He was 89.

A coach whose foundation is still paying off.

Brunell led the CCHS boys cross country program from 1978 to 1996, guiding the team through what his obituary calls "its state championship years." The program he helped build has kept thriving long after his tenure ended — the CCHS boys won the MIAA Division 1B State Championship at Northfield Mountain in 2024, nearly three decades after Brunell stepped away from coaching.

A path that started far from Concord.

Born Nov. 10, 1936, in East Orange, N.J., Brunell graduated from Nutley High School and earned a bachelor's degree in economics from Union College. He served in the U.S. Army from 1958 to 1960, reaching the rank of private first class as a member of the U.S. Infantry Division Honor Guard and earning commendations for his service. At CCHS, he taught math for years both before and after his time coaching.

A life that never slowed down outside the classroom.

Brunell was an avid outdoorsman who ran marathons, including the Boston Marathon, and pursued kayaking, birding, painting, sculpture and photography, earning recognition for his photography work along the way. He volunteered with the Wellfleet Audubon Sanctuary on Cape Cod, the Boulder County Nature Center, and the New England Aquarium — a lifetime spent giving back to the natural world he clearly loved.

Family and remembrance.

Brunell was predeceased by his brother Kurt Brunell and his longtime partner, Diane Sanger. He is survived by brothers Roger Brunell of Gulfport, Miss., and Duane Brunell of East Boothbay, Maine, along with several nieces and nephews, including Jeff Brunell, Emily Pious and Ryn Grant.

A Celebration of Life is planned for Cape Cod in September, with details to follow. Memorial donations may be made in Brunell's name to Massachusetts Audubon, 208 South Great Road, Lincoln, MA 01773. Arrangements are under the care of Hall Funeral Home of Boothbay, where condolences can be shared at hallfuneralhomes.com.