Dennis G. Sullivan “Sully” entered the gates of Heaven on Tuesday, August 18th, 2026, at the age of 72, following a courageous two-year battle with esophageal cancer.
Dennis was born on November 28th, 1953, in Milwaukee, Wisconsin to Bob and Cathy Sullivan. He grew up in Milwaukee, where he developed his strong work ethic, sense of humor, and love for family that would define his life. He graduated from James Madison High School in 1972, where he was a gifted athlete who excelled in many sports including basketball, football and especially baseball. As a catcher, his talent and dedication on the field earned him a scholarship to the University of Wisconsin-Madison. His years as an athlete were a source of great pride and reflected the determination and competitiveness that remained a part of who he was throughout his life.
Dennis was a devoted husband, father, Papa, brother, uncle, and friend whose greatest joy in life was his family. He is survived by his loving wife of 45 years, Pauline Sullivan; his three daughters, Kelsey (Steve) Sperl, Deanna (Joseph) Orlofski, and Mallary (Andrew) Sedlmeier; his seven beloved grandchildren, Isla, Skylar and Sully Sperl, Abram and Hank Orlofski, and Luca and Laney Sedlmeier. He is also survived by his siblings, Gary (Lora) Sullivan, Kim (John) Hagie, Kelley (Dave) Schroeder, as well as many nieces, nephews, extended family members, and dear friends who will forever cherish his memory. Dennis is preceded in death by his parents, Bob and Cathy Sullivan.
Dennis’s legacy lives on through the values he instilled, the kindness he shared, and the countless lives he touched throughout the years. He was truly larger than life, loud, full of personality, and always ready for a good time. A welder for almost 40 years, he was hardworking and proud of the life he built. He was a passionate sports enthusiast, especially when it came to Wisconsin teams, and he loved fantasy football, friendly banter, and sharing laughs with friends.
Music was one of Dennis's greatest passions. As the drummer for The Flunk Band, featuring 60’s rock and roll, he spent more than a decade playing music with friends, and he never lost his appreciation for the rock-and-roll songs he grew up with. Whether behind a drum kit or listening to his favorite songs, Dennis passed that love of music on to his children and grandchildren.
While Dennis enjoyed many things in life, nothing compared to the pride he felt for his family. His daughters were an immense source of joy, and he adored his grandchildren beyond measure. In retirement, the role he cherished most was simply being "Papa." He spent countless hours cheering on his children and grandchildren at their sporting events,
performances, and activities, bringing the same enthusiasm whether he was watching soccer, baseball, basketball, dance recitals, or a school play. If one of his children or grandchildren were involved, Papa was there, proud and fully invested.
Dennis also loved the home he and Pauline built together in Menomonee Falls, where they lived for 38 years and raised their family. Five years ago, they began a new chapter in Germantown, Wisconsin, and enjoyed creating new memories in a home that quickly became the gathering place for family and friends. No matter where he lived, he took tremendous pride in his yard and spent countless hours creating beautiful gardens, making every place he called home warm and welcoming.
He will be remembered for his big personality, unmistakable presence, love of sports and good times, and, above all, the profound pride he had in his family and the unwavering devotion he showed them throughout his life.
Visitation will be held on Thursday, August 27th, 2026, at Good Shepherd Catholic Church (N88W17658 Christman Rd, Menomonee Falls, WI 53051) at 2:00pm., followed by Mass at 4:00pm. Following the service, please join the family at The Hot House Tavern (N88 W16631 Appleton Ave, Menomonee Falls, WI 53051) for food, drinks and a celebration of Dennis’s life. Family and friends are welcome to gather, share memories, and honor his legacy.
