He was born in Oranienbaum as Count George of Carlow; he was the youngest child and only son of Duke George Alexander of Mecklenburg (6 June 1859 – Saint Petersburg, 5 December 1909) and his morganatic wife (m. Remplin, 6 June 1889) Nataliya Fyodorovna Vanlarskaya, Countess of Carlow (Saint Petersburg, 16 May 1858 – Cannes, 14 March 1921), daughter of Fyodor Ardalionovich Vanlarsky (Dagoutze Chavli, Georgia, 23 December 1835 – 2 February 1903) and wife Mariya Fyodorovna Uvarova, and granddaughter of Ardalion Alexeievich Vanlarsky, born in Poretchie, near Smolensk, and wife Tatyana, daughter of Mariya Mikhailovna Litvinova.

The Grand Ducal family then moved to Grunewald, where they lived until their home was destroyed in an Allied bombing raid in February 1944.

[7] In August 1944, George was arrested by the Gestapo and sent to Sachsenhausen concentration camp by the Nazi government, where he remained until February 1945.

Duke George was married firstly in Geneva, Switzerland, on 7 October 1920 to Irina Mikhailovna Raievskya, Countess Tolstoy (Tsarskoye Selo, 18 August 1892 – Sigmaringen, 22 January 1955) the widow of Count Alexander Mikhailovich Tolstoy (Saint Petersburg, 17 January 1888 – Mishkor, Crimea, 19 February 1918), daughter of Mikhail Nikolaievich Rayevsky (1841–1893) and Princess Mariya Grigoryevna Gagarina (Tiflis, 14 June 1851 – Cannes, 2 August 1941) and granddaughter of Nikolai Nikolaievich Rayevsky (14 September 1801 – 1843) and wife (m. 22 January 1839) Anya Mikhailovna Borozdine, and Prince Grigory Grigoryevich Gagarin and wife Sofiya Andreievna Dashkova.

[10] The children who survived into adulthood were: In May 1956 George became engaged to Archduchess Charlotte of Austria,[12] a daughter of the last Austrian Emperor, Charles I and Zita of Bourbon-Parma.