In the presence of a thiyl radical species, the catalytic Markovnikov thiol–ene reaction is challenging because it prefers to proceed via a radical pathway, thereby leading to anti-Markovnikov selectivity. In this work, a rare example of thiyl radical engaged in Markovnikov thiol–ene reaction enabled by cobalt catalysis is reported. This protocol features the avoidance of unique oxidants, exclusive regioselectivity, and broad substrate scope. Scalable synthesis and late-stage modification of complex molecules demonstrate the practicability of the protocol.