After completing his A-levels, civilian service and training as a tax clerk, he went on to study at the University of Cologne, specialising in business taxation, tax law and auditing.

While still a student, he started working in the corporate tax department of an international auditing company and worked there for 10 years. During this time, he passed his tax advisor exam. At the beginning of 2015, Mr Schmitz joined Zacharias & Demmer. He has been a partner and co-partner since 2022.