After being seriously wounded in September 1943, Fegelein was reassigned by Heinrich Himmler to Hitler's headquarters staff as his liaison officer and representative of the SS.

Historian Michael D. Miller describes Fegelein as an opportunist and careerist who ingratiated himself with Himmler, who granted him the best assignments and rapid promotions.

[7] On 25 July 1937, Reichsführer-SS Himmler, by special order of the SS-Oberabschnitt Süd, created the Haupt-Reitschule München (SS Main Riding School) in Munich.

[11] Fegelein won the "Braunes Band von Deutschland" (Brown Ribbon of Germany), an annual horse race which in 1938 was held on the premises of the riding school in Munich.

[12] In September 1939, Fegelein commanded the SS Totenkopf Reiterstandarte (Death's-Head Horse Regiment), which arrived in Poland shortly after the end of the Polish Campaign.

[14] Fegelein's unit was involved alongside the Orpo in the extermination, ordered by Hitler, of members of the Polish elite such as intellectuals, aristocrats, and clergy, in an action called Intelligenzaktion.

[17] On 23 April 1941, Fegelein faced court-martial charges for an incident in 1940 where he and his unit had been caught stealing money and luxury goods for transportation back to Germany.

While in his report he described the behaviour of his troops as "clean and decent", there were many incidents in this period where his men behaved in an undisciplined way, killing and robbing civilians without being ordered to do so.

[21] In May and June 1940, Fegelein, who had been promoted to SS-Obersturmbannführer of the Reserves in the Waffen-SS on 1 March 1940, participated in the Battle of Belgium and France as a member of the SS-Verfügungstruppe.

[25] Himmler addressed the 1st Cavalry on 5 July, offering the opportunity for any men unwilling to participate in the upcoming "special tasks" to transfer to another unit.

[26] On 19 July 1941, Himmler assigned Fegelein's regiments to the general command of HSSPF Erich von dem Bach-Zelewski for the "systematic combing" of the Pripyat swamps.

The result was the Pripyat Marshes massacres, an operation designed to round up and exterminate Jews, partisans and civilians in that area of Byelorussian SSR.

[27] Himmler's orders for the operation were passed to Fegelein via SS-Brigadefuhrer Kurt Knoblauch, who met with him and Bach-Zelewski on 28 July in their new quarters at Liakhovichi in Byelorussia.

[32] Fegelein's final report on the operation, dated 18 September 1941, states that they killed 14,178 Jews, 1,001 partisans, 699 Red Army soldiers, with 830 prisoners taken and losses of 17 dead, 36 wounded, and 3 missing.

[22] Massive counter-attacks by the Red Army led to a weakening of the entire German line, and the brigade was called in to fight at the front on 28 December.

[39] The brigade was deployed at the south-eastern sector of the XXIII Army Corps, where it defended against attacks in the rearward area of the 206th Infantry Division in the Battles of Rzhev.

Fegelein was then granted home leave and was appointed Inspector of Cavalry and Transportation (Inspekteur des Reit- und Fahrwesens) in the SS-Führungshauptamt on 1 May 1942.

During Weichsel (27 May – 10 June 1943) he reported the unit had killed 4,018 persons and deported 18,860, confiscated 21,000 cattle, and destroyed 61 villages southwest of Gomel.

[2] On 20 July 1944, Fegelein was present at the failed attempt on Hitler's life at the Wolf's Lair headquarters in Rastenburg, East Prussia and received a minor wound to his left thigh from the bomb blast.

Eva was glad to have someone in the entourage with whom she could dance and flirt, as Hitler was distant in social situations and refrained from publicly showing affection.

Fegelein consistently attended Bormann's drinking parties and told Junge that the only things that mattered were "his career and a life full of fun.

[55] On 27 April 1945, Reichssicherheitsdienst (RSD) deputy commander SS-Obersturmbannführer Peter Högl was sent out from the Reich Chancellery to find Fegelein, who had abandoned his post at the Führerbunker after deciding he did not want to "join a suicide pact".

That night, Hitler was informed of the BBC broadcast of a Reuters news report about Himmler's attempted negotiations with the western Allies via Count Folke Bernadotte.

SS-Brigadeführer Wilhelm Mohnke, who presided over the court martial for desertion, told O'Donnell that Hitler ordered him to set up a tribunal.

Mohnke arranged for a court martial panel, which consisted of generals Wilhelm Burgdorf, Hans Krebs, SS-Gruppenführer Johann Rattenhuber, and himself.

[68] At this point the accounts differ, as the NKVD dossier states that Fegelein was court-martialed on the evening of 28 April, by a court headed by Mohnke, SS-Obersturmbannführer Alfred Krause, and SS-Sturmbannführer Herbert Kaschula.

[70] Journalist William L. Shirer and historian Ian Kershaw characterise Fegelein as cynical and disreputable;[47][48] Albert Speer called him "one of the most disgusting people in Hitler's circle".

[1] Historian Michael D. Miller describes Fegelein as an opportunist who ingratiated himself with Himmler, who in return granted him the best assignments—mostly related to cavalry—and rapid promotion through the ranks.

[2][71] The historian Henning Pieper, who studied the period up until March 1942, notes Fegelein's lack of formal training as an officer led to deficiencies in the way the SS Cavalry Brigade was prepared for active service.

[72] Fegelein repeatedly overstated the combat readiness of his troops and exaggerated their accomplishments, in Pieper's opinion in order to be seen as a leader worthy of promotion and honours.