Participants gathered in the Polish southern city's historic market square carrying candles and flowers to remember the victims, show solidarity with those injured and offer support to their families.
The march passed three sites where people were killed in the attack, state news agency PAP reported.
At 8 p.m., church bells rang out, followed by the traditional bugle call from St. Mary's Basilica, one of Kraków's best-known symbols.
Nawrocki, Tusk and Kraków Mayor Łukasz Gibała laid candles at the sites of the killings.
The march ended near the Town Hall Tower, where a trumpeter played "The Sound of Silence," the Simon and Garfunkel song also performed at memorial events for Gdańsk Mayor Paweł Adamowicz, who was fatally stabbed in 2019.
Cardinal Grzegorz Ryś, the Catholic archbishop of Kraków, then led the crowd in the Lord's Prayer and a prayer for the dead.
Nawrocki and Tusk, who are political opponents, appeared together at the event in a show of solidarity after an attack that has shocked the country and prompted a dispute over the gunman's possible motives.
Six people were killed and 16 injured when a 24-year-old Polish man, identified by prosecutors as Michał Oksiński, drove into the market square on Saturday and opened fire on passers-by.
The suspect was shot by police and taken into custody. He died in hospital early on Monday.
Those killed included a 32-year-old British man and a 51-year-old Austrian woman.
The other four were Polish citizens—three women and one man.
Nationals of Germany, Portugal, Britain, Austria and Russia were among those injured, according to the interior ministry.
Two police officers were wounded while confronting the gunman.
Prosecutors' spokesman Przemysław Nowak said on Monday that both had regained consciousness.
Tusk wrote on X that one officer, Artur Morański, asked about his injured colleague Jakub Kulik as he woke up.
Fifteen people injured in the attack remained in hospital, regional governor Krzysztof Kleczar said.
Fourteen were in stable condition, while one of the officers who helped apprehend the attacker remained in serious condition.
Family members found dead
Police also found the bodies of Oksiński's parents and 21-year-old sister at the family home in the south-central town of Ostrowiec Świętokrzyski.
Preliminary findings indicate that he may have killed them while they were asleep before driving to Kraków.
The shooting in Kraków's historic main square, a UNESCO World Heritage site and one of Poland’s most popular tourist destinations, has shocked the country.
'Gadsden flag'
Speaking about the gunman's motives on Saturday, Interior Minister Marcin Kierwiński said initial findings suggested the attacker might have been inspired by far-right ideology.
The right-wing opposition criticised the statement, with Law and Justice (PiS) party leader Jarosław Kaczyński calling the claims a "blatant lie."
National Public Prosecutor's Office spokesman Przemysław Nowak told reporters on Monday that investigators did not yet know what had motivated the killer.
He said police had found a so-called Gadsden flag in Oksiński's room, a historical American yellow banner featuring a rattlesnake and the words "Don’t Tread on Me" in the attacker's room.
The design dates back to the American Revolutionary War in the 18th century.
Nowak said the flag was associated with "various meanings related to freedom or rebellion" but was not widely recognised as a symbol linked to extremism.
Interior ministry spokeswoman Karolina Gałecka said investigators had also found numerous emblems on the gunman's clothing, some of which had already been examined and interpreted.
Justice Minister Waldemar Żurek said the investigation would continue despite the man's death, with prosecutors seeking to establish whether he had acted alone or been inspired by a group.
Gałecka said Poland's Central Bureau for Combating Cybercrime (CBZC) had detained five people over online posts praising Oksiński’s actions.
She added that police were on high alert for potential copycats following the attack in Kraków.
Nowak said four firearms and several hundred rounds of ammunition had been found in the attacker's car and among his belongings.
"We secured a very large number of spent casings. In total, at least several dozen shots were fired, possibly even several hundred," he added.
Kraków remains in mourning through November 11, while a period of national mourning declared by Nawrocki ends on Monday.
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Source: IAR/PAP, TVP Info/TVN24, Reuters