Kazys Grinius was born on 17 December 1866 in Selemos Būda village, Sasnava rural district, Marijampolė county.

From 1914 through to 1919 Kazys Grinius and his family lived in Russia. In 1917 he was elected to the Russian Lithuanian Council in Voronezh. In 1919 he went to Paris, chaired the Repatriation Commission of the Lithuanian delegation; worked for the return of Lithuanians from German captivity, helping around 1,000 of compatriots.

Kazys Grinius returned to Lithuania in 1919. He was a member of the Constituent Seimas, 1st, 2nd and 3rd Seimas; from 19 June 1920 to 2 February 1922, he headed the 6th Cabinet of Ministers. In 1922, Kazys Grinius became director of the Health and Sanitary Division of Kaunas Municipality.

On 7 June 1926, Kazys Grinius was elected President of the Republic of Lithuania and remained in office until the coup d'état on 17 December 1926.


During the Nazi occupation, Kazys Grinius was exiled to Ažuolų Būda for protesting against the killings of Jews.

In 1944, he fled to the West, arriving to Chicago (USA) in 1947.

Kazys Grinius was one of the leaders of the Peasant Populist Union; an important member of the Varpininkai group (working for the monthly "Varpas" - The Bell); he was among the authors of the program of the Lithuanian Democratic Party (1906).

He edited "Lietuvos ūkininko kalendorius" (Lithuanian Farmer's Calendar), "Ūkininkas" (Farmer), "Varpas", "Sveikata" (Health), "Lietuvos žinios" (Lithuanian News), "Kova su džiova" (Fighting Tuberculosis), "Pieno lašas" (Drop of Milk); contributed to "Aušrinė" (Morning Star), "Lietuvos ūkininkas" (Lithuanian Farmer), "Vilniaus žinios" (Vilnius News); translated into Lithuanian and published issues No. 1 and 2 of "Lietuvos darbininkas" (Lithuanian Worker).

Kazys Grinius left works on botany, medicine and history, translations of fiction and popular science from Polish and other languages, as well as two volumes of memoirs.

Kazys Grinius died on 4 June 1950 in Chicago.