The selective cleavage of carbon–carbon (C–C) bonds has emerged as a powerful tool for molecular deconstruction and skeletal editing. However, the inherent strength and low polarity of C–C bonds render their selective scission a formidable challenge. Alkenes are some of the most important chemicals in the chemical industry and synthetic community. Selective deconstructive functionalization of alkenes to produce densely functionalized molecular scaffolds is highly attractive but challenging. This review focuses on the development of C–C bond functionalization of olefins. While traditional approaches have predominantly involved cleavage of the double bond itself, recent advances have opened two distinct and complementary pathways: (1) the selective cleavage of robust σ-bonds adjacent to the double bond, including C(vinyl)–C and allylic C–C linkages, while preserving the valuable alkene moiety and (2) the transformative cleavage and reconstruction of the double bond through novel processes such as single-atom (nitrogen or carbon) insertion, moving beyond conventional metathesis. This review comprehensively summarizes these groundbreaking developments, highlighting the mechanistic principles and synthetic applications that are expanding the toolbox for complex molecule synthesis and editing.