Josef Kammhuber was born in Alz, the a son of a farmer. When World War I started he was 18 and joined a Bavarian engineer battalion. He experienced Verdun in 1916 and was promoted to second lieutenant in 1917. He remained in German's tiny post-war army, and in 1925 was promoted to first lieutenant. His rise through the ranks continued slowly but in 1929 he was sent for pilot training and promoted to captain. He was sent to the USSR in 1930 and 31 in order to train in secret, and on his return was sent to join the staff of General Walter Wever who was in the process of attempting to set up a strategic bomber command, a plan that died with Wever in 1936.
After Wever's death Kammhuber was promoted to colonel in 1938. After it became clear that the RAF was starting a massive building program, Hitler decided to match their expansion and proposed a program worth about 60,000,000,000 RM. The German aircraft industry was incapable of matching this sort of request, due to both construction and material shortages, and the leadership within the Luftwaffe realized it was impossible. The chiefs of staff, Jeschonnek, Kammhuber and Stumpf, then put forth Kammhuber's own plan for about 1/3rd the production levels, which they felt they could meet. Milch organised a meeting between them and Hermann Göring, in which Göring said that Hitler's programme should be carried out as planned, confident that "somehow" they could meet his quotas.
Kammhuber, realizing what was going on, put in a request in February 1939 for active duty. He was transferred to France where he became Kommodore of a KG51, a tactical bomber unit. During the French campaign he was shot down and captured, and interned in a French POW camp at the age of 44. He was released at the end of the Battle of France and returned to Germany.
Once again an officer of the Luftwaffe's Generalstab, in July 1940 he was placed in command of coordinating flak, searchlight and radar units. At the time they were all under separate command and had no single reporting chain, so much of the experience of the different units was not being shared. The result was the XII Fliegerkorps, a new dedicated night-fighting command.
He organized the night fighting units into a chain known as the Kammhuber Line, in which a series of radar stations with overlapping coverage were layer three deep from Denmark to the middle of France, each covering a zone about 32km long (north-south) and 20km wide (east-west). Each control center was known as a Himmelbett zone, consisting of a Freya radar with a range of about 100km, a number of searchlights spread through the cell, and one primary and one backup night fighter assigned to the cell. RAF bombers flying into Germany or France would have to cross the line at some point, and the radar would direct a searchlight to illuminate the plane. Once this had happened other manually-controlled searchlights would also pick up the plane, and the night fighter would be directed to intercept of the now-lit bomber. However, demands by the burgomasters (Bürgermeister) in Germany led to the recall of the searchlights to the major cities.
Later versions of the Himmelbett added two Würzburg radars, with a range of about 30km. Unlike the early-warning Freya, Würzburg's were accurate (and complex) tracking radars. One would be locked onto the night fighter as soon as it entered the cell. After the Freya picked up a target the second Würzburg would lock onto it, thereby allowing controllers in the Himmelbett center to get continual readings on the positions of both planes, controlling them to a visual incerception. To aid in this, a number of the night fighers were fitted with a short-range infra-red device known as Spanner, but these proved almost useless in practice.
Another tactic that proved effective was to send their own planes to England while the raids were taking off or landing. Radio operators listening to the RAF bomber frequencies were able to recognize the start of a raid, and the raiding force of about 30 night fighters would be sent over the RAF airbases to shoot down the bombers as they took off or landed. By the beginning of October the night intruder force had claimed a hundred kills but on October 13th Hitler ordered the force sent to the Mediterranean despite their success. On October 16, 1940 he was promoted to Generaloberst with the charge of "General of the Night Fighters" and established his HQ in Utrecht, the Netherlands.
British intelligence soon discovered the nature of the Kammhuber Line and started studying ways to defeat it. At the time Bomber Command sent in their planes one at a time in order to force the defenses to be spread as far apart as possible, meaning that any one aircraft would have to deal with little concentrated flak. However this also meant the Himmelbett centers were only dealing with perhaps one or two planes at a time, making their job much easier. At the urging of RV Jones, Bomber Command reorganized their attacks against a single target at a time, sending all of the bombers in a single "stream", carefully positioned to fly right down the middle of a cell. Now the Himmelbett centers were facing hundreds of bombers, countering with only a few planes of their own. So successful was this tactic that the success rate of the night fighters dropped almost to zero, and Kammhuber was soon being looked at with suspicion by Milch and Göring.
Kammhuber started looking for solutions, and the result was the two-prong concept of wilde sau and samte sau. In the former, thought up by Hans-Joachim "Hajo" Herrmann, day fighters would be sent up and look for the bombers from the light of flares dropped from light bombers, searchlights set to a wide beam or illuminating lower clouds, or the fires on the ground below. The wilde sau force scored their most notable success during the bombing of Peenemünde on August 17, 1943. deHavilland Mosquito bombers had dropped target marker flares ove Berlin and most of the night fighter force was sent there. When it was realized what was really happening, most of these planes were too far away and to slow to intercept the raid. However the much faster Focke-Wulf Fw 190's being flown by the wilde sau forces were able to easily catch them, and about 30 planes entered the stream and shot down 29 of the 40 bombers lost that raid.
Samte sau envisioned freeing the night fighters, now equipped with radar for the final stages of the interception, from the Himmelbett cells and allowing them to attack on their own. This was not all that easy given the current generation of radars, but newer systems being developed would greatly increase the detection range and angles. In this role the existing cells created as part of the original Kammhuber Line would be used primarily for early warning and vectoring the planes to the stream.
At the same time Kammhuber continued to press for a new dedicated nightfighter design, eventually selecting the Heinkel He 219 Uhu after seeing it demonstrated in 1942. However Milch had selected this design for cancellation, and fighting broke out between the two. Thus in 1943 Kammhuber was transferred to Luftflotte 5 in Norway, in command of a handful of outdated planes. In 1945 he was re-appointed to command of the night fighters, at this point a largely ceremonial position considering the state of the Third Reich at that time.
After the fall of the Reich, Kammhuber wrote a series of monographs on the conduct of the German defences against the RAF and USAAF. These were later collected into book form as Fighting the Bombers: The Luftwaffe's Struggle against the Allied Bomber Offensive. In 1953 he published a definitive work on what he learned during the war as Problems in the Conduct of a Day and Night Defensive Air War.
Josef Kammhuber returned to Germany and joined the Luftwaffe while it was re-forming. He was promoted to Inspekteur der Bundesluftwaffe, serving in that role between 1956 and 1962.