In his 20s and early 30s, von Braun was the central figure in Germany's pre-war rocket development programme, responsible for the design and realization of the deadly V-2 combat rocket during World War II. After the war, he and some of his rocket team were taken to the United States as part of the then-secret Operation Paperclip. In 1955, ten years after entering the country, von Braun became a naturalized U.S. citizen.

Von Braun worked on the US Army intermediate range ballistic missile (IRBM) program before his group was assimilated by NASA, under which he served as director of the newly formed Marshall Space Flight Center and as the chief architect of the Saturn V launch vehicle, the superbooster that propelled the Apollo spacecraft to the Moon. According to one NASA source, he is "without doubt, the greatest rocket scientist in history. His crowning achievement ... was to lead the development of the Saturn V booster rocket that helped land the first men on the Moon in July 1969." He received the 1975 National Medal of Science.

Wernher von Braun was born in Wirsitz (Wyrzysk), Province of Posen, then a part of the German Empire, and was the second of three sons. He belonged to a minor aristocratic family, inheriting the German title of Freiherr (equivalent to Baron). His father, conservative civil servant Magnus Freiherr von Braun (1878–1972), served as a Minister of Agriculture in the Federal Cabinet during the Weimar Republic. His mother, Emmy von Quistorp (1886–1959), could trace her ancestry through both parents to medieval European royalty. Von Braun had a younger brother, also named Magnus Freiherr von Braun. After Wernher von Braun's Lutheran confirmation, his mother gave him a telescope, and he developed a passion for astronomy. When Wyrzysk returned to Poland at the end of World War I, his family, like many other German families, moved to Germany. They settled in Berlin, where 12-year-old von Braun, inspired by speed records established by Max Valier and Fritz von Opel in rocket-propelled cars, caused a major disruption in a crowded street by detonating a toy wagon to which he had attached a number of fireworks. He was taken into custody by the local police until his father came to collect him.

Von Braun was an accomplished amateur musician who could play Beethoven and Bach from memory. Von Braun learned to play the cello and the piano at an early age and originally wanted to become a composer. He took lessons from Paul Hindemith, the famous composer. The few pieces of von Braun’s youthful compositions that exist are reminiscent of Hindemith’s style.

Beginning in 1925, von Braun attended a boarding school at Ettersburg Castle near Weimar where he did not do well in physics and mathematics. In 1928 his parents moved him to the Hermann-Lietz-Internat (also a residential school) on the East Frisian North Sea island of Spiekeroog. There he acquired a copy of Die Rakete zu den Planetenräumen (1929) (By Rocket into Interplanetary Space) (in German) OCLC 6026491 by rocket pioneer Hermann Oberth. Space travel had always fascinated von Braun, and from then on he applied himself to physics and mathematics to pursue his interest in rocketry.

In 1930 he attended the Technical University of Berlin, where he joined the Verein für Raumschiffahrt (VfR, the "Spaceflight Society") and assisted Willy Ley in his liquid-fueled rocket motor tests in conjunction with Hermann Oberth. He also studied at ETH Zurich. Although he worked mainly on military rockets in his later years there, space travel remained his primary interest.

He was greatly influenced by Oberth, and he said of him:

Hermann Oberth was the first, who when thinking about the possibility of spaceships grabbed a slide-rule and presented mathematically analyzed concepts and designs.... I, myself, owe to him not only the guiding-star of my life, but also my first contact with the theoretical and practical aspects of rocketry and space travel. A place of honor should be reserved in the history of science and technology for his ground-breaking contributions in the field of astronautics.

Von Braun was working on his creative doctorate when the National Socialist German Workers Party (NSDAP, or Nazi party) was elected to power in Germany, and rocketry almost immediately became a national agenda. An artillery captain, Walter Dornberger, arranged an Ordnance Department research grant for him, and von Braun then worked next to Dornberger's existing solid-fuel rocket test site at Kummersdorf. He was awarded a doctorate in physics (aerospace engineering) on July 27, 1934 from the University of Berlin for a thesis titled About Combustion Tests; his doctoral advisor was Erich Schumann. However, this thesis was only the public part of von Braun's work. His actual full thesis, Construction, Theoretical, and Experimental Solution to the Problem of the Liquid Propellant Rocket (dated April 16, 1934) was kept classified by the army, and was not published until 1960. By the end of 1934, his group had successfully launched two rockets that rose to heights of 2.2 and 3.5 kilometers.

At the time, Germany was highly interested in American physicist Robert H. Goddard's research. Before 1939, German scientists occasionally contacted Goddard directly with technical questions. Wernher von Braun used Goddard's plans from various journals and incorporated them into the building of the Aggregat (A) series of rockets. The A-4 rocket is the well known V-2. In 1963, von Braun reflected on the history of rocketry, and said of Goddard's work: "His rockets ... may have been rather crude by present-day standards, but they blazed the trail and incorporated many features used in our most modern rockets and space vehicles." Goddard confirmed his work was used by von Braun in 1944, shortly before the Nazis began firing V-2s at England. A V2 crashed in Sweden and some parts were sent to an Annapolis lab where Goddard was doing research for the Navy. If this was the so-called Bäckebo Bomb, it had been procured by the British in exchange for Spitfires; Annapolis would have received some parts from them. Goddard is reported to have recognized components he had invented, and inferred that his brainchild had been turned into a weapon.