He always remembered Warsaw with nostalgia. The independent city was a witness to his games with siblings and friends, youthful adventures and love conquests. He recorded the colourful years of the interwar period in Ostatnia Cyganeria (The Last Bohemia) and in several biographies, including those of Hanna Ordon, Stefan Wiechecki-Wiech and Bolesław Wieniawa-Długoszowski. This carefree life ended in September 1939, which the author depicted in his poem Piosenka (Song):
They glide across the sky from afar
Clouds like white sheep,
And in these clouds as in milk
The bombers come in.
Wittlin took part in the defence of the capital, but at the beginning of 1940, he was arrested by the Soviets and deported to a labour camp in Vorkuta. He included these experiences in his camp stories Diabeł w Raju (Devil in Paradise), whilst in Joyful Days he noted:
The Polish Army in Russia, organised from half-dead shadows, torn by the violence of death, came into being under conditions never to be understood by anyone who was not there at the time.
After his release from the camp, he joined the Anders Army, with which he reached the Holy Land. He finally had the cap with the eagle he had longed for, and even ‘a belt with a crosspiece, though made of very vile camel hide’. He wrote: ‘In a tropical helmet, an identical shirt and shorts revealing bare knees, I tread the sunny streets of green Tehran’. In one of his poems, he compared the foreign, ‘modern capitals’ of the Middle East to the ‘ugly’ but ‘most beautiful and more precious with every day’ streets of Warsaw. In the Anders Army, he served as a cultural animator. He published in magazines and publications of the 2nd Corps (Orzeł Biały, Parada and Zew), as well as in the civilian Polish press published in Jerusalem and Rome.
After the war he went to London and then to Paris, where he worked in the Polish section of a French radio station. At the beginning of the 1950s, he emigrated to the United States, and in 1958 he settled permanently in Washington. He prepared literary programmes for Głos Amaryki (Voice of America) and Radio Free Europe. In the 1960s, he became editor of the monthly magazine Ameryka, which reached Poland. He lectured on Polish literature at Washington University.