Kazys Grinius was born in 1866 December 17 in Marijampolė county, Sasnava village, Selemos Būda village. in 1887 graduated from Marijampolė gymnasium. In the same year, he entered the Faculty of Medicine of Moscow University. In 1893 after receiving the degree of medical doctor, he worked as a doctor on a ship in the Caspian Sea. In 1894 returned to Lithuania. He practiced as a doctor in Marijampolė and was actively involved in Lithuanian cultural and social activities. He was one of the leaders of the Peasants' People's Union and the leaders of the Varpininkai Organization.

The First World War drove K. Grinius and his family to Russia. In 1896 he married Joana Pavalkytė, with whom he had sons Jurgis and Kazys and daughter Gražina (in 1918, his wife and daughter were brutally killed by marauding soldiers in Kislovodsk).

In 1917 In Voronezh, K. Grinius became a member of the Supreme Council of Lithuanians in Russia and the chairman of the Council. In 1919 went to France, was invited to the delegation of the Lithuanian Provisional Government at the Peace Conference, became the chairman of the Lithuanian Repatriation Commission. Helped compatriots to return from German captivity to Lithuania. In the fall of the same year, he returned to Lithuania, where at that time the first democratic elections of the Constituent Parliament were already being prepared.

Kazys Grinius was a member of the Constituent Parliament, I, II and III. He took care of health protection issues, defended the freedom of self-determination and civil rights of national minorities. Since 1920 June 19 until 1922 February 2 headed the 6th Cabinet of Ministers.

In 1926 June 7 The III Parliament elected Kazys Grinius as the President of the Republic of Lithuania. He led the Republic of Lithuania until 1926 until the December 17, when the coup plotters forced the president to resign.

In 1927 K. Grinius married Kristina Arsaitė, they had a son Liūtas.

During the German occupation - November 14, 1942 - dr. Kazys Grinius and former Lithuanian ministers Prof. Jonas Pranas Aleksa and prof. Reverend Mykolas Krupavičius signed and delivered a memorandum on behalf of the Lithuanian nation to the general commissar of the occupying German army in Lithuania, Gauleiter Adrian von Renteln. At the time, it meant a voluntary path to death: immediate firing or a torturous death in a concentration camp, historians believe. The memorandum protested the colonization of Lithuania, the repression of Lithuanians, Poles, Russians, and the massacre of Jews. The foreign press at the time was surprised that three Lithuanians openly challenged the Nazis, when many were afraid to even whisper a hostile word. J.P. Aleksa and M. Krupavičius were deported to Germany by the Gestapo. President Kazys Grinius was sentenced to house arrest and exile to his native village of Selemos Būda.

Kazys Grinius and his wife Kristina proved their determination to defend innocently murdered fellow citizens not only by words, but also by deeds. Dmitrijus Gelpernas (1914-1998), deputy commander of the Anti-Fascist Struggle Organization of the Kaunas Ghetto, testified to the Spielberg Foundation that when the Nazis attacked the Soviet Union, he tried to retreat to the East, but the German army overtook them, so he had to return to Kaunas. On the way, Dmitry Gelpern met Chaim Jelina and his family. Before the establishment of the ghetto, he and Chaim Jelin hid at D. Gelpern's relative. The men did not leave the house because they knew that Jewish men were being killed right on the street. D. Gelpern's relative was Kristina Griniuvienė's student friend. Griniuvienė also knew Dmitriy very well because both were interested in stamps and sometimes exchanged them. One day, the relative met K. Griniuvienė in the city and told her that Dima Gelpernas was also in Kaunas. K. Griniuvienė said that, if necessary, she is ready to help. But D. Gelpernas moved to the ghetto together with other Kaunas Jews that time. However, after the Great Campaign, they decided to turn to Grinius for help. They received him warmly, gave him a separate room. Dmitry used to eat together with the Grinius family at the same table. Sometimes guests came to the Grinius, but they did not hide D. Gelpern from their friends, there were no anti-Semites among them. Mr. Gelpernas lived in the Grinius house for several months, but sometimes he went out into the city, joined the column of Jews which were coming back from work, and thus were able to get in the ghetto. Grinius provided Gelpern with medication and told him information that interested him.

Dmitry Gelpern's companion, professor Sara Ginaitė, a former prisoner of the Kaunas ghetto and a participant in the anti-Nazi resistance, remembers that D. Gelpernas hid with the Grinius family during the entire first winter of the Nazi occupation until the deportation of President Kazys Grinius to Selemos Būda.

Kazys Grinius died in 1950. June 4 in Chicago. In 1994 October 8 the urn with the remains of President K. Grinius was brought to his homeland and buried in a larch grove near Selemos Būda.