His father Bernhard Löwenstein had a clothing shop, which brought the family a modest income.
Between 1904 and 1907, Löwenstein studied Theology and Philosophy in Halberstadt and he was accepted into the orthodox Rabbi school in Berlin.
When they got married, they signed the following marriage contract[1] which is a proof of their progressive thinking and acting concerning gender equality: §1 On 1 April 1911 both of the contracties, out of free choice and based on love, agree to found the marriage upon equal rights and responsibilities.
However, by a word of honour they declare that the responsibilities and rights, described in the state marital contract will not apply as they find them redundant.
A pacifist, Löwenstein applied to join the Red Cross in 1914 in Grodno (Belarus) where he took care of injured soldiers until 1918.
From 1924 to 1933 he was the president of German Children's friend movement (ReichsArbeitsGemeinschaft der Kinderfreunde), now the Socialist Youth of Germany – Falcons.