The purpose of this study was to design the life cycle of sponsorship in Iranian professional sport. The research was conducted through a qualitative approach in two sequential phases. In the first phase, the Delphi technique was utilized to delineate the foundational coordinate axes, define the sequential development stages, and determine the structural properties of the sponsorship life cycle. The expert panel comprised 15 key informants encompassing academic scholars in sport management and sport marketing, professional club executives, corporate sponsorship directors, and senior sport policy-makers. In the second phase, applying Glaser’s grounded theory methodology, 23 in-depth semi-structured interviews were conducted with professional club managers, corporate sponsorship decision-makers, academic specialists, and governing sport officials, followed by systematic open, selective, and theoretical coding procedures. The Delphi findings revealed that the horizontal coordinate represents time or sponsorship duration, whereas the vertical coordinate reflects sponsorship intensity or financial magnitude. Consequently, four foundational phases—introduction/initiation, growth/development, maturity/peak, and decline/reduction—alongside two divergent trajectories—renewal/revival or termination/dissolution—were established. The grounded theory findings further demonstrated that the sponsorship trajectory is governed by entry prerequisites, relationship growth mechanisms, maturity sustainers, decline triggers, dynamic macro-environmental forces (economic, legal, institutional, and media contexts), and strategic regeneration pathways. Overall, sponsorship in Iranian professional sport emerges as a dynamic, stage-contingent, and manageable partnership; its long-term viability requires mutual trust, operational transparency, strict fulfillment of obligations, strategic media activation, bilateral value co-creation, and meticulous sponsor experience management amid prevailing institutional and economic frameworks.