Dennis William Sullivan, 69, of Lake Mary, Florida passed away January 8, 2018 at the Florida Hospital Lake Mary Emergency Clinic . He is survived by his wife Mary Ann Sullivan of Lake Mary, Florida, two daughters and son-in-laws, Carrie Ann Cloud of Atlanta, Georgia and her husband Brooks Cloud, Jennifer Marie McCombs and her husband Justin McCombs of Sanford, Florida, one son, Patrick Joseph Sullivan of Lake Mary, Florida, three grandsons, Darien Sullivan, Finn McCombs, Wyatt Cloud, one granddaughter, Avery Sullivan, and many cousins.   Dennis established Dennis W. Sullivan & Associates, Inc. in 1983 and built it into a successful financial planning business. He attained numerous awards throughout his career. He loved meeting people and established many close friendships with his clients. His motto was "Work Hard, Play Hard".  He and his wife Mary Ann traveled extensively. He embraced his Irish heritage and was so thrilled to visit Ireland in 2015. Dennis enjoyed working out at the gym and running was his passion, completing two marathons in 2004. He is pre-deceased by his parents, Mary and Ernest Sullivan and a sister Mary Beth Sullivan. A Celebration of Life will be held at 11:00 a.m. on Friday, January 19, 2018 at Northland Church, 530 Dog Track Road, Longwood, Florida 32750.