Dragoslav Siljak was born in 1933 in Belgrade; He played Water Polo for Partizan Belgrade and Jadran Hercegnovi. When he was 18 years old he joined the Yugoslavian National team and won the silver medal at the 1952 Olympic Games in Helsinki, the silver at the 1953 World Championship in the Netherlands and the 4th place at the 1960 Olympics in Rome. Balancing his love for Water Polo and science Siljak, entered the University of Belgrade and earned his doctorate. In 1964 he moved to Santa Clara University, building a research base centered around parameter space methods for the design of control systems. The developed methods were used by NASA Marshal Space Center in the control design of spacecraft including the Saturn V rocket that carried astronauts to the moon.