Online teaching results in knowledge-building. Knowledge-building is the teaching and learning process that helps academics and students to generate specific personal values used to understand their personal identities. Academics have been forced by COVID-19 lockdowns to go online in teaching their students. The purpose of this study is to explore and understand academics' knowledge of teaching for knowledge building in two higher-education institutions (HEIs) (RSA and USA) during the COVID-19 era and the 4IR. Reflective activities, focus-group discussions, and semi-structured interviews were used for data generation. Purposive with convenience sampling was used to select the twenty most accessible academics to participate in this study. The findings reveal that this situation compelled the academics to self-actualise on their knowledge-building to address the "why" questions of teaching that help students to understand and address their needs. The self-actualization was framed by "technological pedagogical content knowledge" which produced societal, personal, and professional knowledge building. It was interesting to note that the USA HEI participants were supported by educational technologists, while the RSA HEI participants helped themselves. This was because the RSA HEIs do not have educational technology centres. Consequently, this study recommends a follow-up study that can qualitatively and quantitatively compare the two HEIs. In this way it can be established whether the success of online teaching and learning is influenced by the presence of educational technology centres. Educational technology centres have educational developers/technologists whose main responsibility is to collaborate with academics, various departments, and HEI units on a range of research/teaching/learning/assessment activities.