Dr. Leonard E. Kosinski, 69, of Woodstock, Georgia, passed away on November 26, 2025, surrounded by family, after courageously battling cancer. Leonard was born on October 24, 1956, in Pittsburgh, Pennsylvania, to the late Leonard and Claire Kosinski. He was preceded in death by his beloved wife, Carla Kosinski.

Leonard is survived by his children: Mary Kosinski, Leno Kosinski, Joyce Kosinski and her husband, Daniel Diamicis, and Max Kosinski. He was the cherished grandfather of Theodore Heddleston, Reagan Heddleston, Daniel Leonard Diamicis, and Claire Diamicis. Leonard is also survived by his brother, Jim Kosinski, and his wife, Sue; and his sister, Beth Winkempleck, and her husband, Brian.

A resident of Woodstock for the past 21 years, Leonard was a proud graduate of La Salle University and Purdue University. He enjoyed a distinguished career with DuPont, where he was responsible for numerous breakthroughs and held multiple patents for his work. Specializing in polymers, Leonard earned deep respect within the scientific community for his innovation, dedication, and outstanding contributions to the field.

Leonard was known for his quick wit, sharp intellect, and his unwavering love for his family. He expressed his care through cooking, often preparing meals that brought the family together and created lasting memories.

A memorial service will be held on Saturday, December 6, 2025, from 1:00 PM to 3:00 PM, at Lakeside Funeral Home, located at 121 Claremore Drive, Woodstock, GA 30188.