This study aims to investigate how to leverage knowledge sharing (KS) to boost team creativity among information technology (IT) professionals. We examine the effects of intrinsic and intangible extrinsic rewards on in-role and extra-role KS, which increases team creativity. We use data collected from 322 employees in 80 teams from organizations in the IT industry to test the research model and confirm the important roles of KS and motivational rewards. The two types of KS show different patterns in terms of their antecedents and outcomes. Specifically, in-role KS does not affect team creativity directly, while extra-role KS does. Intrinsic rewards significantly affect both in-role and extra-role KS, and the effect on the latter is greater. Image rewards have a greater effect on in-role KS than on extra-role KS. In addition, the two forms of intangible extrinsic rewards exhibit internalization. The study pioneers in addressing a pressing research gap by investigating and comparing the effects of the two types of KS—in-role and extra-role KS—on team creativity.