Unlike most veterinarians, Dr. Rieck (or Dr. Zack to many of his clients) felt the call to animal care later in life, after military service and a career in aviation maintenance. His ultimate career choice was largely influenced by his early exposure to animal science through his father, a wildlife biologist. He has fond childhood memories of being chased around the living room by a raccoon and petting a wild hawk.

He graduated from the University of Wisconsin-Milwaukee majoring in Biology and received his veterinary medicine degree from the University of Wisconsin-Madison in 2013. He sings in a local German choir and plays trumpet in a number of community bands and orchestras alongside his wife, Tristann, who owns a music store in Milwaukee.

Aside from music, Dr. Rieck's hobbies include candle making, woodworking, cooking, gardening, and art.