- Degree in business administration (EBS)
- Career in various German and international companies in the media and telecommunications industry
- Chairman of the executive committee of Talkline
- January 1998: Chairman of the board of directors of DeTe Mobil, later chairman of the board of T-Mobile International AG
- 2001: Appointment to the board of directors of Deutsche Telekom AG
- 2002–2006: CEO of Deutsche Telekom AG
- Executive chairman and partner at Delta Partners, an international private equity company, focus on telecommunications in developing/emerging countries
- Investor in companies in the telecom sector and board member at various companies such as Kabel B.-W., United Internet AG, and euNetorks Ltd.