Writing for the Court, Justice Elena Kagan held that specific personal jurisdiction exists when [1] a defendant has “purposefully availed” itself of conducting activities in the forum state and [2] the plaintiff’s claims “arise out of or relate to” those contacts. Interpreting the “arise out of or relate to” element, the Court rejected the requirement of a strict causal link between the defendant’s contacts and the plaintiff’s claim and instead held that the “or” included in the phrase creates two independent pathways to jurisdiction. Justice Kagan explained that when a manufacturer systematically serves a market in the forum state and their product causes injury there, the state’s courts have the power to exercise jurisdiction regardless of where the specific product was designed, manufactured, or first sold, and stated two underlying principles behind this rule. First, Justice Kagan posited that the principle of fairness through reciprocity implies that when a company enjoys the benefits and protections of state law through extensive business operations, the state may hold it accountable for related misconduct and the company receives fair warning it will face jurisdiction where it systematically markets products. Second, Justice Kagan argued that the principle of interstate federalism implies that states with significant interests in a controversy being able to exercise jurisdiction over a dispute arising from or relating to their state rather than the case being heard in a jurisdiction with minimal connections.​

In this case, Ford conceded it had purposefully availed itself of both Montana’s and Minnesota’s markets through their extensive operations. This included dozens of dealerships, targeted advertising of their vehicles, comprehensive repair services, and a vast network of replacement parts distribution. This left the question of whether their activity sufficiently “related to” the plaintiff’s claims arising from in-state product malfunctions. Justice Kagan found that since Ford had systematically served the markets for the very vehicle models that were alleged to have malfunctioned and injured the plaintiffs, such a connection existed. She explained that Ford’s advertising, accessible service, available parts, and active resale market potentially influenced residents’ purchasing decisions, and requiring proof of these causal chains would be impractical. On the principle of fairness, Justice Kagan argued that Ford enjoyed substantial benefits from operations in these states and had clear notice it could be subject to a lawsuit where its marketed products caused injury. Additionally, Montana and Minnesota had compelling interests in providing convenient forums for their citizens injured in such cases and enforcing safety regulations.