Joseph Bruce Greiner Obituary 

Joseph Bruce Greiner, age 95, of Jupiter, Florida and Remsenburg, New York, passed away at home surrounded by family on Wednesday, November 12, 2025. He was born on February 7, 1930 in New York City to the late Dr. Louis Greiner, who emigrated as a child from Austria, and Dorothy (née Walderman) Greiner of greater Baltimore.

Joe was the youngest of three children, Marilyn (née Greiner) Schaff and William Greiner, who both predeceased him. Joe was the older brother of two half-siblings, Luise Greiner (who predeceased him) and Stephen Greiner. He grew up in Manhattan, attending Stuyvesant High School, where he nurtured his love of chemistry, photography, and cinema and built lifelong friendships, especially with fellow students Dr. Siegfried Johannes “Ziggy” Kra and Dr. Stuart Wolfe, both of whom recently passed. He attended Syracuse University and later transferred to pursue pre-med studies at City College of New York, where he rejoined his friends Stu and Ziggy and became obsessed with bridge, often playing until the early morning hours.
 
After attending medical school at the Sorbonne in Paris for a year, he returned to the U.S. and worked briefly in the insurance industry before finding his path in industrial real estate, first with his brother Bill, who had co-founded Greiner-Maltz. He launched his own firm, J.B. Greiner Company, an industrial and commercial real estate brokerage firm focused on Queens and Brooklyn, which he ran for nearly 40 years. Known as a master negotiator with the highest ethical standards, Joe was highly entrepreneurial, forming partnerships with fellow brokers and developers and investing strategically in a market that he studied carefully. He also taught real estate as an adjunct at NYU. An achievement Joe was most proud of was the successful negotiation of a deal that brought the Long Island City Citibank tower to fruition, which sparked the massive development boom that followed in that area. 
 
Joe enjoyed an active and rewarding 30+ year retirement with his second wife, Sigrid Weschky Greiner, who predeceased him. He pursued his passions for tennis, cooking, computers, and tech investing. He spent decades enjoying “adult summer camp” in Jupiter with an expansive set of dear friends who became a second family. Joe was at the center of entertaining and connecting his friends. As a snowbird, Joe spent the summer months in Remsenburg, where he created a family compound for his children, grandchildren, and extended family to enjoy. 

Until the very end of his life Joe was a force of nature with a powerful intellect who modeled determination, kindness, generosity, wisdom, diplomacy, humor, and love. 
 
He is survived by his children, Dawn (Glenn) Kasten, Jennifer (Jacob Ouillette) Greiner, and John (Mary) Greiner; grandchildren Julia, Liam, and Eleanor Greiner, and Aidan Kasten; step-grandchildren Stephanie and Aurora Kasten; brother Stephen (Marilyn) Greiner, and sister-in-law Inge Weschky; ex-wife and mother of his children, Dorothy Greiner; cousins, nieces, nephews, dear friends, and his beloved dog, Daisy.
 
There will be a Celebration of Life in Jupiter, Florida on February 19, 2026. In lieu of flowers, the family welcomes donations in his memory to the Furry Friends Animal Shelter (https://ffhumane.org/) in Jupiter, Florida or New York Junior Tennis and Learning (https://www.nyjtl.org/) in Long Island City. 

Please feel free to add your special memories of Joe on the tribute wall and if you would like more information on the Celebration of Life on February 19, 2026 in Jupiter, Florida, please email at dawn.kasten@gmail.com asking for the information.