An inventor’s exploratory innovation is driven by an extensive external knowledge search. This paper contributes to this understanding by exploring how inventors’ brokerages dynamic influence exploratory innovation from the perspective of ego-network, and the moderating role of knowledge diversity is also explored. Specifically, we define an inventor’s direct partners (tier-1) as brokerages between the inventor and its indirect partners (tier-2) and discuss the effects of the inventor’s brokerage expansion, stability, and recession on its exploratory innovation. Our empirical research is based on 4198 inventors working in the artificial intelligence field during the period from 1991 to 2019, and we identify those inventors through the USPTO database. Our results indicate that the brokerage expansion of an inventor has an inverted U-shaped impact on exploratory innovation, the brokerage stability has a positive impact on exploratory innovation, and the brokerage recession has a negative impact on exploratory innovation. Furthermore, knowledge diversity strengthens the positive impact of brokerage expansion and stability on exploratory innovation and strengthens the negative impact of brokerage recession on exploratory innovation.