Her career began as an artist in Melbourne, where her oil paintings were displayed and sold. She transitioned into the world of advertising, which took her from Sydney to Hong Kong and to New York in 1997, where she became the architect of numerous campaigns for various companies, including Pfizer, Hong Kong Bank and Georgia-Pacific. (She was also a writer, contributing to the Daily Beast and Business Insider, and she wrote and directed the 2003 award-winning documentary “Sin Embargo: Never the Less,” on the resilience of the Cuban people.)

“Judith is simply brilliant,” said Jennifer Pybus, a friend and business partner.

“In the world of advertising, she is formidable, she’s the real deal,” Ms. Pybus said. “She’s elevated and reinvented so many brands for some of the best agencies in the world. She somehow knows what people want before they even know they want it.”

Ms. Grey, who no longer had a need to look up Mr. Kelly online, learned firsthand that he was the son of Veronica and Raymond W. Kelly and had grown up in Garden City, N.Y. His father, also a former Marine, served two stints as New York City police commissioner.

Mr. Kelly graduated from Fordham University with a bachelor’s degree in political science and went on to serve nine years as an attack pilot in the United States Marine Corps, specializing in flying the AV-8B Harrier jet. During his service, Mr. Kelly amassed 158 aircraft carrier landings and flew over Iraq in Operation Southern Watch, enforcing the United Nations-imposed no-fly zone.

“Greg was a bit of a maverick back then,” said Ossen D’Haiti, a fellow Marine pilot and longtime friend who served with Mr. Kelly in the early 1990s. “He’s the kind of guy you want in your squadron. He doesn’t get too uptight, and finds levity in everything he does.”