The past two decades have witnessed explosive growth in the field of catalytic C-H activation. While this reactivity is typically associated with second- and third-row transition metals, first-row transition metals are also capable of catalyzing these reactions. C-H activation reactions can be further divided into ones where the C-H activation occurs with a low-valent metal and those where the activation occurs with a high-valent metal. This review will summarize advances in the area of high-valent Co(III)- and Ni(II)-catalyzed C-H activation with particular emphasis paid to how these catalysts compare their second- and third-row congeners.