At 19, Klein worked as a joiner at the time of the Nazi German invasion of Poland in World War II, when he was taken to the Maidanek concentration camp along with his father.

He managed to return to his old house, which was occupied by local Poles, who told him "that's what happens in war times, what is your today becomes someone else's tomorrow", and called a police officer claiming Samuel was invading his property which led him to spend a night in custody.

[6] After five years, in 1957, he had accumulated sufficient capital to open his first shop in downtown São Caetano do Sul, which he called "Casa Bahia".

The rapid growth of the organization, and Klein's role in building it into a regional economic force were the subject of one of the case studies in C. K. Prahalad's Fortune at the Bottom of the Pyramid.

Via Varejo was soon formed through the mergers of Casas Bahia with Ponto Frio and Extra Eletro, both owned by Grupo Pão de Açúcar.

[22][23] In December 2020, the website UOL had access to court proceedings that revealed that Samuel Klein used the cash register of Casas Bahia stores to pay underage call girls.

In many cases, the women went to Casas Bahia stores with tickets signed by Samuel Klein himself, causing embarrassing situations for the employees.

[25][26] Káthia Lemos, accused by the report of being one of the groomers of underage girls for Samuel Klein, says that she actually acted to get poor women whom the businessman did not want to stop offering themselves in return for presents or monetary benefits.

A lawyer heard by Agência Pública says that he closed a court settlement, with a confidentiality pact, where the case contained videos that proved Samuel Klein's sex crimes.

[...] We vehemently repudiate any and all types of harassment, illegal practices and discriminatory acts on our premises, including our administrative headquarters and our stores."

[27] In July 2021 Agência Pública released a story going deeper into the accusations which showed the alleged child abuse by Klein had lasted from 1983 to 2013 according to testimonials.