In 2021, Felix alongside members Lee Know and Hyunjin became the endorser for Italian luxury label Etro's unisex Earthbeat sneaker. In August 2023, he was selected to be a house ambassador for Louis Vuitton.
Felix began consistent donations and sponsorship for the international children's rights organization, Save the Children, in 2020. His contributions made him appointed as a member of the Honours Club. He also donated ₩50 million (equivalent to $38,500 in 2023) to aid the relief efforts following the earthquake in Turkey and Syria on 6 February. In January 2024, Felix donated ₩100 million (equivalent to $76,100 in 2024) to the Korean Committee for UNICEF to help Laos children living in poor sanitation and nutritional environments, becoming the youngest member of the UNICEF Honors Club.