In 1919, Vailokaitis co-founded the Farmers' Association on which ticket he was elected to the Constituent Assembly of Lithuania in April 1920.

He resigned from the Constituent Assembly in March 1922, but continued to be influential in the ruling Lithuanian Christian Democratic Party.

Together with his brother, Vailokaitis established Ūkio bankas which became the largest commercial bank in interwar Lithuania.

Using profits from the bank, Vailokaitis brothers established or bought several industrial enterprises, most successful of which were Palemonas (brickyard) and Metalas (metal factory).

Vailokaitis supported various charitable causes, including financial backing for the Klaipėda Revolt, land donation to the newly established University of Lithuania, and scholarships to about 200 Lithuanian students.

Jonas Vailokaitis was born on 25 June 1866 in Pikžirniai [lt] near Sintautai to a family of affluent Lithuanian farmers.

[8] At the outbreak of World War I in August 1914, the company relocated to Vilnius and started selling supplies to the Russian Imperial Army.

[9] In September 1917, Vailokaitis attended Vilnius Conference which discussed Lithuania's political aspirations after the war.

For example, he suggested that the Council of Lithuania take out a loan of 10 million rubles, protested German military requisitions, and opposed making commitments to Germany regarding custom duties in the Act of 11 December.

[16] In 1919, Vailokaitis together with his brother Juozas, Mykolas Krupavičius, and Aleksandras Stulginskis worked to established the Farmers' Association.

Initially, it was a clone of the pre-war Žagrė cooperative: it sought to improve farmer's economic conditions by providing agricultural equipment and fertilizer.

[19] He supported the establishment of the Bank of Lithuania, issuance of Lithuanian litas, austerity measures to deal with budget deficits, tax reform (reducing reliance on indirect taxes), and the land reform which would nationalize nobility's landholdings and distribute them to small farmers.

[21] On 16 February 1919, Vailokaitis together with Aleksandras Stulginskis, Andrius Dubinskas [lt], and Pijus Grajauskas founded Ūkio bankas which became the largest commercial bank in interwar Lithuania.

[27][28] Using profits from the bank, Vailokaitis brothers established or bought several industrial enterprises, including Palemonas (brick), Metalas (metal), Maistas (food), Medis (lumber), Venta (lumber mill), Spėka (fish), Linas (flax), Eksimportas (import-export), Urmas (wholesale).

[29] Palemonas, established in 1922 in a suburb of Kaunas near a railway and a peatbog (which provided fuel), was the largest producer of bricks and tiles in Lithuania.

The factory produced agricultural machines and tools, chains, wire, nails, buckets, and other metal goods.

[34] This loan was fiercely criticized by the political opposition, including Augustinas Voldemaras, but a special revision commission found no improprieties.

[36] His critics and opponents accused him of profiting from such trade: Lithuanian workers were paid in litas but did not trust this new currency and hurried to exchange it to German Papiermarks that soon became worthless due to the hyperinflation.

[39] Vailokaitis provided financial backing to the Klaipėda Revolt in January 1923: he donated US$12,500 (equivalent to $223,500 in 2023) for the cause and pledged another $10,000 if needed.

[40] Vailokaitis also supported the newly established University of Lithuania by donating a 16-hectare (40-acre) plot of land for the construction of the Physics and Chemistry Institute in 1925.

[41] Vailokaitis also donated to other charitable causes,[1] including providing scholarships to about 200 Lithuanian students via Ūkio bankas.

At first, he worked in the section dealing with Lithuanian trade with England and Germany (largest export partners of Lithuania).

[23] According to a report by British consul G. W. Berry, Vailokaitis continued to have great influence among the Lithuanian Christian Democratic Party.

[50] In turn, Vailokaitis promised to exert his influence on the Farmers' Association so that its members voted for the ratification of the Non-Aggression Pact in the Third Seimas.

An urn with his cremated remains was reburied next to his brother Juozas in the cemetery of Paštuva [lt] village on 18 August 2007.

Vailokaitis was accused of currency speculation,[37] taking cheap loans from the Bank of Lithuania and then reloaning the money at much inflated interest to others, avoidance of taxes, using government funds to prop up his failing business ventures, etc.

Its proclamations painted Vailokaitis as a corrupt leech stealing Lithuania's riches and as a foreign agent of France, Poland, or United States.

[41] Teofilis Tilvytis wrote a satirical poem Letter to Vailokaitis in which he expressed joy for the end of the bourgeois and start of the communist regimes.

[60] Around 1930, Vailokaitis family built a luxurious six-floor house by architect Arno Funk [lt] in Kaunas.

[65] It was visited by many prominent Lithuanians, including poet Maironis, writer Vincas Mykolaitis-Putinas, singer Kipras Petrauskas, President Aleksandras Stulginskis.