Denise Brennan-Rieder Obituary

With immense sadness we announce the passing of Denise Brennan-Rieder on September 3, 2025. Denise was born in Dublin, Ireland, daughter of Jim (predeceased) and Ann Brennan, adored sister to Geraldine (predeceased), Susanne, Colm, Donal and Cormac.

Denise is survived by her spouse Stephen, with whom she forged a very close and loving relationship ever since their meeting in 1994. She was a proud, loving and supportive mother to son Calvin and daughter Ciara, devoting herself tirelessly to their well-being and development. She was the centre of her closely knit family and would go far out of her way to ensure everyone's health and happiness.

Denise was educated in Ireland, achieving her PhD in Zoology and worked in medical research, specializing in protein chemistry and endocrinology in a number of institutions in Ireland, the USA and Australia. She was nature-oriented and loved to further her understanding of the natural order of our beautiful and fragile environment, strongly believing in preservation and sustainability. She continued her learning and discovery through science and engineering projects undertaken by Calvin and shared beautiful experiences in accompanying him to many events including the Canada-Wide, ISEF and Google Science Fairs.

Denise travelled the world adventurously in her earlier years and met Stephen in Sydney, Australia, where they married and welcomed son Calvin into the world. They relocated to New York in 1998 and daughter Ciara was born in New Jersey in 2000. Subsequently they settled in Canada and lived here until her passing.

Denise loved gardening, swimming, photography, art, culture, music and reading. Her broad knowledge on many topics was regularly tested by viewing British quiz shows Mastermind and University Challenge, which she loved to share with Calvin. To the end, she explored new subjects online or by reading and would share discoveries with her family. She delighted in the pottery skillfully created by Ciara and was so proud of her recently appointed residency at the Art Gallery of Burlington. She loved the peace and beauty of the family cottage and wouldn't shy away from swimming even in frigid fall conditions. She also loved music and attended many live concerts over the years, in more recent times sharing a passion for opera and classical music.

A Funeral Mass for Denise will be celebrated on Saturday, September 20, 2025 at 10 a.m. at St. James Parish in Oakville (231 Morden Road).

In lieu of flowers, the family asks that donations be made to Doctors Without Borders in memory of Dr. Denise Brennan-Rieder by using the Donations tab on her homepage.