In the 1988 Summer Olympics, together with teammate Arvydas Sabonis, Marčiulionis led the senior USSR national team to the gold medal.

Given that Laimutė aggravated a spinal injury while giving birth to his sister Zita, her determination in having a son led to the middle name Šarūnas, invoking a legendary knight from Vincas Krėvė-Mickevičius's works.

[7] While Marčiulionis signed a contract with Atlanta, the day after he won the gold medal in the 1988 Summer Olympics, the team wound up not submitting it to the NBA's offices, as the Soviets said they would not permit the player to leave.

[8] Eventually, Nelson's influence helped Marčiulionis with his social projects in Vilnius, and led him to remain with the Warriors, with whom he signed a three-year $3.8 million contract, in 1989.

After missing a year-and-a-half with a leg injury, he was traded, along with Byron Houston, to the Seattle SuperSonics in 1994 in exchange for Carlos Rogers, Ricky Pierce, and two 1995 second-round draft picks.

He contacted prospective players, encouraged several to join, selected the uniforms, negotiated a shoe deal, and arranged for sponsorships, along with friend Donnie Nelson.

[14] Sponsor deals struck by him included Bank of America and the rock band Grateful Dead, who were interested in supporting Lithuania, after reading a story on Marčiulionis and the national team, in the San Francisco Chronicle.

The Grateful Dead also helped launch a line of tie-dyed jerseys, that would feature Lithuania's national colors,[4] along with a slam dunking skeleton, created by New York artist Greg Speirs.

Marčiulionis' basketball career and journey to represent his native country Lithuania in the 1992 Barcelona Olympics is highlighted in the documentary film "The Other Dream Team".

In 1987, he helped a Panevėžys man get an artificial heart valve for his son, by appealing to Donnie Nelson, who arranged an operation for the teenager in the United States.

[5] In the aftermath of the 1989 San Francisco earthquake, Marčiulionis appeared at the site of a commuter train accident, wearing his Warriors warm up outfit, and he helped by pulling out trapped passengers and administering first aid.

[33] After he joined the Warriors, Marčiulionis's wife Inga enrolled at Merritt College, where she walked on to their women's basketball team and was a star player for two seasons.

[38] Šarūnas' son Augustas Marčiulionis made his debut in the Lithuanian Basketball League on September 19, 2020, as a member of his father's first professional team Rytas Vilnius.