Death Announced of Kathleen Mary O’Brien, Married in Old Lyme, Mother of Two New Yorkers, Drawn Back to the Shore

Kathleen Mary O’Brien passed away peacefully on May 3, 2026, at the age of 58, at home in Old Lyme, surrounded by love.

Kathy was born on January 13, 1968, daughter of Daniel and Margaret O’Brien of East Haddam, Connecticut. As the firstborn, she quickly claimed her place as the family’s golden child – a role she relished until she discovered one she loved even more: that of big sister to Daniel and Jennifer. She remained a golden child for the rest of her life, but was happy to share the title with her beloved siblings.

Kathy was kind, generous, and fun-loving – a luminous soul, with a brilliant smile and a laugh that echoed through the house. She had a gift for making life feel bigger, brighter, and full of joy. She was someone who said yes: to friendship, to adventure, to travel, and to all the wonder the world had to offer. She especially loved packing up her little crew and exploring new places together, creating memories her family will carry forever.

Kathy graduated from Mercy High School in Middletown and went on to Northeastern University in Boston, forming lifelong friendships in both places. She later moved to New York City, where she enjoyed a brilliant career in marketing and advertising, most notably at Grey Advertising, Ericsson Fina, and McCann Worldwide. In New York, she met Jesse Vendley – quite possibly the luckiest man in the world – with whom she built a beautiful life and raised two born-and-bred New Yorkers, Nathaniel and Margot.

Of all the roles Kathy played so well – daughter, sister, friend, colleague, wife – none mattered more to her than being a mother. Devoted, proud, and endlessly loving, Kathy delighted in motherhood. Being Nate and Margot’s mom was the greatest joy of her life.

In later years, with Nate and Margot grown and Kathy’s illness progressing, she and Jesse moved to Old Lyme, the place where they had been married 24 years earlier. There, Kathy could be closer to many of the things she loved most: her family, her garden, and sunsets and lobster rolls along the Connecticut shore.

Kathy is survived by her husband, Jesse, and their children, Nathaniel and Margot; her parents, Daniel and Margaret O’Brien; her siblings and their partners, Daniel O’Brien and Jennifer and Michael Cassineri; her beloved nieces and nephews, Maeve, Grace, James, and Jackson; her wonderful aunts, uncles, cousins, and in-laws; and close friends from every stage of her life.

A memorial service for Kathy will be held at the Essex Yacht Club in Essex, Connecticut, on Sunday, June 7, from 1 to 4 p.m. All who knew and loved her are welcome.

Kathy filled her life – and the lives of those around her – with warmth, laughter, beauty, and love. She will be missed beyond measure, and remembered with joy.