Daniel August Dohnalek

With deep sadness, the Dohnalek family shares the passing of Daniel August Dohnalek, of Lake Forest, IL on May 18, 2026. Lovingly known as Dad, GranDan, Danny Boy, and Dr. Dan, he was a devoted husband, father, grandfather, brother, uncle and trusted friend. Born in Chicago on March 25, 1957, to the late Jeanne O'Neil and Donald Dohnalek, Dan grew up in Glenview. As the eldest of five children, he welcomed the responsibility of guiding and caring for his younger siblings. Dan was a self-taught entrepreneur who began building his business knowledge at a young age. He started a handyman service in elementary school, even creating his own business cards by hand. He continued to work independently throughout all his school years while also excelling in both academics and athletics. He was a leader in the Student Council and NHS at Glenbrook South High School. Dan was on the varsity tennis team and was a standout goalkeeper on the soccer team where he was captain his senior year. He was awarded a scholarship to play soccer at Indiana University. As a member of the Kappa Sigma fraternity, he served as Rush Chair while making lifelong friendships. After graduating, he attended the University of Illinois College of Dentistry, finishing ahead of schedule as he was eager to begin his career. He started working at a small dental practice in Lake Zurich, IL that he soon acquired. He grew the practice through hard work and community involvement, including volunteering as a soccer coach at local schools. It was here in Lake Zurich where he developed lifelong relationships with his patients and their families. Dan continued to serve the Lake Zurich practice for over 40 years with the same quality patient care that defined his career from the very beginning. Dan was best known for his calm and reassuring chairside manner and his gift for making his patients laugh. Partnering with a close friend in 1996, he co-founded Manus Health Systems, a dental practice management group. He grew a single practice into a respected, multi-specialty organization serving patients throughout the Chicagoland area. Over the years, he and his business partner expanded, acquiring practices across the region, including the dental practices of the University of Chicago and Northwestern University. In 2017, Manus partnered with Shore Capital and became the foundation for their dental platform, Great Lakes Dental Partners. Dan served on the Board and as Clinical Director, where he mentored and supported new doctors. Dan’s legacy lives on through the practices he built, the doctors he mentored, the clinical teams he guided, the staff he supported and the countless patients whose lives he improved. Dan met his wife Cathy at a friend’s engagement party, and their connection was instant. He proposed as they flew over the vineyards of Napa Valley in a hot air balloon. After their wedding, they made their home in the historic community of Lake Forest along the beautiful shore of Lake Michigan, where they built a life centered on love, deep friendship, and the joy of raising their family together. Above all, Dan’s family was his everything. They welcomed their first son, Hayden, in 1992, and their second, Nolan, in 1995. Dan treasured fatherhood, instilling Christian values in his sons from their earliest years. He taught them to embrace responsibility. Alongside Cathy, he taught Sunday School and organized monthly volunteer activities, making service a natural part of their family life. This was a calling that eventually took them on mission trips across the country and the world. That same fatherly love extended to other members of the family, their collies Ribbon and Nala, and their border collie Layla, who may have been the only one in their home with more energy than Dan. Though he thought he was only a dog dad, Nolan surprised him once with two kittens, followed by three more kittens, who Dan loved all the same. Nala still sits at the front window, day after day, waiting for him to come home. Dan's greatest joys were found at home and on the road with his sons. He was their first coach and their biggest fan in every sport. Dan introduced them to many things, even taking his family to Honduras for a week-long scuba certification course. He passed along his love of animals to his sons, a passion that traced back to his days as a zoology major in college. He helped fulfill Nolan's dream of visiting every baseball stadium around the country, while deep-sea fishing trips with Hayden became their own tradition. The love of the game ran in the family. For Dan, what began with a pair of childhood baseball pajamas grew into a lifelong love for the Chicago White Sox. Dan became a season ticket holder in his 30s, spending summer days taking his boys and their “Cubs fan” friends to countless games. Witnessing the 2005 season and bringing his family to a White Sox World Series victory game was one of the great experiences of his life. Dan also served on the board of the Lake Forest Baseball Association for many years, cheering on Nolan as he developed his own love for the game. Dan dedicated his life to giving his family the opportunities he never had, while passing down the work ethic and perseverance that made them possible. Dan was the definition of a true gentleman. He was composed, polite, and respectful to everyone he met. Those were the same qualities and values he wanted to instill in his sons. It was important to him that they grow up to be men of integrity. One of his great joys was watching Hayden follow in his footsteps into a career in medicine. And though dentists are not known for their networking skills, Dan's frequent introductions opened many doors for Nolan. Dan’s children never had to wonder if their father was proud of them, he told anyone who would listen. They remember Dan getting emotional two times in recent years. The first was when Dan personally placed Hayden’s green doctoral hood at his medical school graduation. The second was when he learned he would soon be a grandfather. Second only to his family and friends was his love of golf. In his late 20s, a childhood dream became reality when he became a golf member of Westmoreland Country Club. Later, he joined Exmoor Country Club, where he and his family embraced all the club had to offer. Dan served on multiple committees and on the Board of Governors. He enjoyed many years as Membership Chair. He was fortunate to have played 19 times in the Highland Fling, Exmoor's premier member-member event. Dan, along with good friends, was a member of the Outpost Club, a national golf society for those who enjoy traveling to experience great courses. He was also a member of Cordillera Ranch Golf Club near his winter home in Boerne, Texas. It was at Cordillera where he had his first hole-in-one, making it even more special because he was playing with Nolan. Dan went on to have two more hole-in-ones at Exmoor and Knollwood Country Clubs. Dan and his wife shared an unusual hobby – bringing historic homes back to life. Over the years, they renovated six of the nine Lake Forest homes they lived in, spanning a range of architectural styles, from an 1860 Italianate to a 1903 Colonial Revival to a 1928 English Tudor. After years of cherishing old-world charm and craftsmanship, and all the surprises and inconvenient quirks that came with it, they decided it was time to build something new. In the Texas Hill Country, near his wife’s family ranch, they found a beautiful piece of property along the Guadalupe River that they called, “A River Runs Through It.” After building their transitional style home, Dan looked at their six-acre backyard and did the obvious thing: he built a par-3 golf course. Dan was hardworking, selfless, and honest — a steady presence in the lives of everyone around him. He was generous with his time, his counsel, and his attention. He had a quiet humor and a gift for making those around him feel comfortable. His energy was endless. He will be remembered most for his positive nature, his generosity, and his encouraging words. Dan is survived by his wife of 37 years, Cathy; his sons, Hayden Mengden Dohnalek (Jillian) and Nolan O'Neil Dohnalek; his grandsons, Walter William and Otto Daniel; his siblings, David (Nancy), Dick (Eileen), Diane (Larry), and Donna; and 14 nieces and nephews. A Memorial Service will be held at First Presbyterian Church of Lake Forest, 700 N. Sheridan Road on Saturday, May 30, 2026 at 1 p.m. followed by a reception in the church's Great Room. Interment will be private. In lieu of flowers, the family kindly requests that memorial donations be made in memory of Dan to the Brennan Rehabilitation Foundation at https://www.brennanrehabfoundation.org/. Dan served on the Advisory Board and was deeply passionate about its mission of providing financial assistance to individuals living with paralysis. Through his vision and unwavering support, Dan played an instrumental role in the growth and advancement of the Rehabilitation Foundation. Funeral arrangements entrusted to Reuland & Turnbough Funeral Directors of Lake Forest (847) 234-9649 or www.RTfunerals.com.

Daniel August Dohnalek

March 25, 1957 - May 18, 2026