Mr. Montes began his career in 1975 as a student intern at Siemens S.A. in Spain. Until 1983, he managed various projects in Madrid and Cambridge, England, in the manufacturing technology sector. In 1987, he moved to Standard Electrica as the marketing director for innovation products and head of the technical office for the Eureka Project. In 1987, he became the director of the Center for the Development of Industrial Technology (CDTI) in the Spanish Ministry of Industry. In 1988, he was made general director and member of the executive management of Alcatel S.A. in Spain. In 1993, he switched to GEC Alsthom Transport, where he was president and chief executive officer.

In 1995, he returned to Siemens S.A., taking on the role of chief executive officer. In 2000, he added the position of chairman of Southwest Europe Region to his responsibilities. In 2005, Mr. Montes was named CEO of the Year in Spain and, in 2006, has reached the ninth position in MERCO Ranking (Spanish Monitor of Corporate Reputation), both in leaders' and companies' rankings, being the first foreign company, the first industrial company and also first company of the electronic sector in such position.