[3][4][5] Born in Rio de Janeiro, son of Portuguese immigrants Amadeu Marques Ferreira (1951) and Maria de Fátima Vieira da Silva Ferreira (1955),[6] Casimiro began to gain prominence first on the Esporte Interativo channel (today TNT Sports Brazil) presenting the program "EI Games", at the same time he participated in the youtube channel "De Sola", a skit humor channel and football content that also belongs to TNT Sports.

[17] In January 2022, he announced that he would leave SBT to invest in other projects[18][19] and on the 22nd of the same month, it was announced that Casimiro would broadcast 16 Campeonato Carioca games on his Twitch lives after closing a partnership with the company LiveMode, which is responsible for managing some championships such as Paulista and Copa do Nordeste.

[20][21] After watching and reacting to the first episode of Netflix's "Neymar - O Caos Perfeito" series, Casimiro managed to beat the record for simultaneous viewers on Twitch in Brazil on 24 January 2022, with more than 545,000 people watching the broadcast,[22] mark that made him reach first place in the largest national broadcasts on the platform, in addition to having also entered the top 10 peak viewership in the history of global Twitch, occupying the ninth place.

[28] On 24 November, during a game between Brazil and Serbia for Group G, Casimiro broke a worldwide record with more than 3.48 million viewers in his livestream in YouTube.

The achievement was previously held by Brazilian sertanejo singer Marília Mendonça, with 3.31 million viewers during a livestream in 2020.