[3] Grinius was born in Selema [lt], near Marijampolė, in the Augustów Governorate of Congress Poland, which was part of the Russian Empire.

He was elected president by the Third Seimas, but served for only six months, as he was deposed in a coup led by Antanas Smetona on the pretext of an imminent communist plot to take over Lithuania.

A nephew of writer and leader of the January Uprising Mikalojus Akelaitis, Vincas could speak Russian and Polish, and owned a small library containing prayer books and the works of Laurynas Ivinskis, Motiejus Valančius and Petras Vileišis.

[10] After graduating in 1887, Grinius began studying medicine at Moscow State University, where he became a member of a secret society of Lithuanian students.

In 1888 at the age of twenty-two, along with Vincas Kudirka, Grinius and six others participated in a gathering in Marijampolė, in the so-called first congress of Lithuanian democrats, where they decided to begin the publication of the newspaper Varpas.

Along with other students he wrote A Short History of Ancient Lithuanians (Trumpa senovės Lietuvių istorija), which was published in 1892 in Tilsit (modern-day Sovetsk).

During vacation, Grinius would travel across Lithuania and distribute Lithuanian newspapers, lead "anti-state propaganda", and collect folklore.

His family home became a center of the Lithuanian cultural movement in the region of Užnemunė (west of the Nemunas river).

[12] Grinius was also one of the founding members of Šviesa in 1905, a society dedicated to the establishment of schools, pedagogical evening courses, bookstores, distribution of Lithuanian publications, and assisting young students.

Although the society was illegal and soon had to be closed down, it was made legal again in 1907 and expanded into as many as twenty-three chapters in the Suwałki Governorate.

Nonetheless the society experienced a search by Tsarist authorities in 1908, after which Grinius among many others were arrested and imprisoned in a prison in Kalvarija.

A member of the secret book smuggling Sietynas organization,[16] Grinius also published on topics such as botany, medicine, and history.

He arrived in the northern Caucasus in 1915, and worked there until 1918, firstly at Nalchik and then as head doctor in a war hospital near Grozny.

In 1917, Grinius, Jonas Jablonskis, and Pranas Mašiotas established the Supreme Council of Lithuanians in Russia in Voronezh, whose purpose was to unite all political parties under a new authority.

During the start of the Russian Civil War Grinius and his family lived in Kislovodsk, where Bolshevik forces shot his wife and fatally injured his daughter on 8 October 1918.

Grinius and his two sons, Kazys and Jurgis, fled to Novorossiysk, from where he boarded a ship to the Mediterrannean Sea to travel to France, before returning to Lithuania in November.

Grinius urged the assembly's speaker Aleksandras Stulginskis to leave his party and prepare laws carefully.

Grinius defended the interests of minorities; he proposed to include Polish representatives in the commission's work, and to allow the Jews to speak in the language of their choice.

On 19 June 1920, Grinius became the prime minister of the Christian Democrat and Peasant Union-led government coalition, a title he kept until 2 February 1922.

However, the government coalition dissolved as the Christian Democrat Party, which sought to recover land for the Catholic church that was confiscated and given to the Orthodox in the Russian Empire, disagreed with the Peasant Union.

Grinius was a member of the political opposition who defended freedom of the press, minority rights, advocated for bigger attention to healthcare and education, and criticized peoples' such as Vincas Krėvė-Mickevičius, Augustinas Voldemaras, Antanas Smetona, and Juozas Purickis call to focus diplomatic efforts towards the USSR; it was hoped that this way Lithuania could get the Vilnius region back under its control and defend itself from Poland.

In 1924, Grinius published an article entitled Mūsų rusofilai (Our Russophiles) in which he wrote that, "It's naive to believe that the USSR, which hasn't abandoned in Tsarist Russian imperialism, will give Vilnius to Lithuania", encouraging the government to rather ally itself with Great Britain and other Baltic countries.

During his tenure, Grinius enacted a non-aggression pact with the Soviet Union, by which it recognized Lithuanian rights to the Vilnius region.

[25] On 17 December 1926, on the evening of Grinius's birthday, a coup was arranged that replaced the government with an authoritarian one headed by the Lithuanian Nationalist Union, the most conservative party at the time.

Grinius called the coup a crime against society, and blamed the nationalists, Christian Democrats, and part of the army for it, stating that the factual and psychological reasons for the coup were deep, reaching back to the first years of independence, when nationalists who represented the wealthiest strata of society had monarchical ambitions.

[31] After the coup, Grinius continued working in the Kaunas city municipality, building the foundation for a healthcare system.

[32] He continued his medical career by heading some health societies, editing the newspaper "Battle with Consumption" (Kova su džiova) and "Drop of Milk" (Pieno lašas), and translating fictional and scientific literature.

[33] During Soviet occupation, Grinius edited the newspaper Liaudies sveikata and headed the Kaunas Hygiene Museum.