George I ya kasance Sarkin Girka daga 30 Maris 1863 har zuwa kisan gilla a 1913. Asalinsa yarima ne dan kasar Denmark, an haife shi a Copenhagen, kuma da alama yana son yin aiki a Rundunar Sojan Ruwa ta Danish.Yana da shekaru 17 kacal a lokacin da majalisar dokokin kasar Girka ta zabe shi a matsayin sarki, wadda ta hambarar da Otto wanda ba shi da farin jini.Manyan Mahukunta ne suka ba da shawara kuma sun goyi bayan nadin nasa: Burtaniya ta Burtaniya da Ireland, daular Faransa ta biyu da daular Rasha .Ya auri Grand Duchess Olga Constantinovna na Rasha a 1867, kuma ya zama sarki na farko na sabuwar daular Girka.Biyu daga cikin 'yan uwansa, Alexandra da Dagmar, sun yi aure a cikin dangin sarauta na Birtaniya da na Rasha.Sarki Edward VII na Birtaniya da Sarkin sarakuna Alexander III na Rasha surukansa ne, kuma George V na Birtaniya, Kirista X na Denmark, Haakon VII na Norway, da Nicholas II na Rasha su ne yayansa.Mulkin George na kusan shekaru 50 (mafi tsayi a tarihin Girka na zamani) yana da alaƙa da ribar yanki yayin da Girka ta kafa matsayinta a Turai kafin Yaƙin Duniya na ɗaya .Biritaniya ta ba da tsibirin Ionian cikin lumana a cikin 1864, yayin da aka mamaye Thessaly daga Daular Usmaniyya bayan yakin Rasha-Turkiyya (1877-1878) .Ba koyaushe Girka ba ta ci nasara a burinta na yanki;An ci nasara a yakin Greco-Turkish (1897).