胡安.內格林在西班牙內戰之初被總理-----弗朗西斯科·卡瓦列羅(英語: Francisco Largo Caballero)任命為財政部部長(1936.9-1937.5)[4],在他的任內,他為了幫助第二共和國對付叛軍(當時納粹德國和法西斯意大利已經開始提供軍事支援給叛軍[6])而當時是財政部部長的胡安.內格林以西班牙國內的黄金為代價換取蘇聯的軍事支援(因為當時的英法兩國採用綏靖主義政策,願意供援助的國家也只有蘇聯)[7][8]。
巴塞隆納5 月事件
巴塞隆納5月事件可謂是他成為總理的關鍵因素,1937.5.3-1937.5.8當時以弗朗西斯科.卡瓦列羅為首的共和國政府與全國勞工聯盟-西班無政府主義聯合會(英文:GNT-FAI)(西班牙無主義聯合會是全國勞工聯盟的附屬組織)因為政治分歧而爆發衝突[9],總理弗朗西斯科.卡瓦列羅被迫辭職,西班牙總統曼努埃以爾·阿薩尼亞(英文: Manuel Azaña)任命胡安.內格林為新一任西班牙第二共和國總理同時也是末代總理,根據北卡羅萊納州大學出版社在2015年出版的《西班牙內戰:革命與反革命》(作者:伯內特.博洛藤(英文:Burnett. Bolloten))提到有關時任西班牙總統曼努埃以爾·阿薩尼亞在任命胡安.內格林總理一事上的看法[10]:
" I decided to entrust Negrin with the formation of the government," wrote Azaña. "The public had expected that I would name Prieto. But it was better to have Prieto head the ministry combining the armed forces, for which there was no other possible candidate. In the premier-ship, his sudden changes of mood, his 'tantrums,' could be inconvenient. I felt that it would be preferable .. . to take advantage of the quiet energy of Negrin."[11]
"close collaboration with the bourgeois republican parties and right-wing Socialists," had brought to fruition the "political maneuver" that had culminated in the "provocation in Barcelona" [15]
,而同年的蘇聯駐英國大使形容當時的胡安.內格林政府:
"the new Premier understood the vital need to cooperate with the Communist party and did not grieve unduly that the Anarchosyndicalists refused to come into his cabinet.He boldly slashed the numbers of ministers from 18 to 9. This made the govern-ment more compact and functional, and, most important, the ratio of Commu-nists within it was considerably higher."[16]
^Bolloten, Burnett; Payne, Stanley G.; Esenwein, George. 45.The Rise of Juan Negrín. The Spanish Civil War. University of North Carolina Press,USA: University of North Carolina Press. 2015-09-28: 474. ISBN 978-1-4696-2446-4. 引文格式1维护：日期与年 (link)
