SOUTH PORTLAND – Leslie P. Kozak passed away peacefully on July 13, 2023, at Dirigo Pines in Orono, surrounded by family and finally freed from the torment of Parkinson’s disease.

Born in Dauphin, Manitoba, on Oct. 28, 1940,Les grew up in a Ukrainian community in Yorkton, Saskatchewan, in the home of his maternal grandparents. A gifted skater, Les attracted the attention of a Toronto Maple Leafs scout when he was 15 years old. That year (1956) he left Yorkton for Toronto and entered the Leaf’s development program at St Michael’s College School, providing Les the opportunity to cultivate his hockey talent and his academics. In 1961, the Leafs assigned Les to the Rochester Americans to further his hockey advancement.

Shortly after arriving in Rochester, Les met the mother of his three children, Anne Motte. In January 1962, the Leafs called Les up for a game against the Detroit Red Wings in Maple Leaf Gardens. He relates in his memoirs, written in 2020, Play Up, Play Up and Play the Game, “I received a pass from Dave Keon in the third period…skated around Marcel Provost and shot the puck past Terry Sawchuk and into the goal with a power and accuracy that surprised even me. In this moment I had fulfilled the dream of a lifetime.” After 11 games with the Leafs, Les went back to Rochester for more ice time, and in a game in Providence sustained a career-ending injury when he fractured his skull.

Les returned to Rochester to continue classes at St. John Fisher College, where he pursued studies in English and chemistry. After graduating in 1964 with a BA in English, Les was awarded a fellowship at the University of Notre Dame where he received a PhD in biochemistry and became an early researcher in the field of molecular biology. Following his post-doctoral studies at Michigan State University, Les joined The Jackson Laboratory (JAX) located in Bar Harbor, Maine, in 1970. He quickly grew to love Mount Desert Island and believed it was a magical place to raise children. He embraced life in Maine–hiking the mountains in Acadia, biking and running on the carriage roads, sailing around the islands, skating on the frozen lakes in the winter, and skiing and hiking at Saddleback.

In 1998, after 28 years at JAX, Les left his beloved Mount Desert Island when offered an endowed chair position at the Pennington Biomedical Research Institute in Baton Rouge, Louisiana. In 2010, Les moved to Poland, as a faculty member at the Polish Academy of Sciences in Olsztyn, where he trained a group of young students to research obesity and diabetes. In 2012, Les became affiliated with MaineHealth Institute for Research in Scarborough, Maine, where he held various positions as a visiting and faculty scientist—a relationship that continued. By the close of his career, Les had become an international leader in exploring the role of energy expenditure in regulating obesity and trained over 25 postdoctoral fellows in molecular genetics and obesity. Many of the research studies he initiated are currently ongoing in laboratories throughout the world. He believed much of his scientific success stemmed from his love of research and competitive desire to win and succeed. During his career, Les published over 120 research manuscripts and numerous book chapters, was a member on editorial boards of journals, and served as a reviewer for grant applications at the National Institutes of Health (NIH).

Les moved to Orono earlier this year to be closer to his children. In recent years, he had spent his time between South Portland and Kenora, Ontario with childhood sweetheart, Loraine Carmichael.

Les, who will be remembered for the twinkle in his eye, is survived by son L. Paul Kozak of Hulls Cove, daughter Virginia Kozak Putnam (Nat Putnam) of Bangor, son Mark Kozak (Robyn Shaw) of Telluride, Colo.; and grandchildren Sam, Meg and Jack Putnam, Finley-Jane Kozak, and Gerritt and Caroline Pekkala. He is also survived by his brother Garry; aunt, Jean Sine; along with nieces, a nephew, and other extended family.

The family thanks the staff at Dirigo Pines for their attentive care during his final months and his physician, Dr. Timothy McAteer of South Portland.

Condolences to the family may be expressed at

Donations in Les’s memory can be made to:

Maine Community

Foundation MaineCF

245 Main St.

Ellsworth, ME 04605 or 


Please include a note indicating that your gift is for the Kozak Family

Scholarship, which his family has established in memory of Les, to support a graduating Mount Desert Island High School student pursuing a STEM career

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