On June 24, 1988 the first massive gathering organized by Sąjūdis took place. There delegates to the 19th All-Union Conference of the Communist Party of the Soviet Union were instructed about Sąjūdis goals. About 100,000 people in Vingis Park greeted the delegates when they came back in July. Another massive event took place on August 23, 1988 when about 250,000 people gathered to protest against the Molotov-Ribbentrop pact and its secret protocol.
On June 19, the first issue of samizdat newspaper "Sąjūdis News" (Lithuanian: Sąjūdžio žinios) was published. In September Sąjūdis published a legal newspaper, "Atgimimas" (English: rebirth). In total about 150 different newspapers were printed supporting Sąjūdis.
In October 1988 Sąjūdis held its founding conference in Vilnius. It elected 35-member council. Most its members were members of the initiative group. Vytautas Landsbergis, a professor of musicology who was not a member of the communist party, became the council's Chairman.
Sąjūdis used mass meetings to advance its goals. At first, Communist Party leaders shunned these meetings, but by mid-1988 their participation became a political necessity. A Sąjūdis rally on June 24, 1988, was attended by Algirdas Brazauskas, then party secretary for industrial affairs. In October 1988, Brazauskas was appointed first secretary of the communist party to replace Songaila. Communist leaders threatened to crack down on Sąjūdis, but backed down in the face of mass protests. Sąjūdis candidates fared well in elections to the Congress of People's Deputies, the newly created Soviet legislative body. Their candidates won in 36 of the 40 districts in which they ran.
In February 1989, Sąjūdis declared that Lithuania had been forcibly annexed by the Soviet Union and that the group's ultimate goal was to achieve independence. Lithuanian sovereignty was proclaimed in May 1989, and Lithuania's incorporation into the Soviet Union was declared illegal.
On 23 August 1989, the 50th Anniversary of the signing of the Nazi-Soviet Molotov-Ribbentrop Pact, a 600-kilometre two million strong human chain reaching from Tallinn to Vilnius focused international attention on the aspirations of the Baltic nations. This demonstration and the coordinated efforts of the three nations became known as The Baltic Way.
In December, the Communist Party of Lithuania seceded from the Communist Party of the Soviet Union and agreed to give up its monopoly on power. In February 1990, Sąjūdis representatives won an absolute majority (101 seats out of 141) in the Supreme Council of the Lithuanian SSR. Vytautas Landsbergis was elected Chairman of the Supreme Council. This led to the declaration of independence on March 11, 1990.