Initiating joint attention (IJA) is key for cooperative success. However, daily cooperative competence requires more than simply achieving a shared goal; the social context has a heavy influence. Thus, examining how individuals cooperate and the factors that contribute to a successful cooperative social context is essential to understanding human cooperation. The present study examined if infants' (*M*age= 14.30, *SD*= 0.63, *N*= 210) IJA (in a non-cooperative task) relates to cooperative success and the social context (affiliative and antagonistic behaviours) during cooperative tasks with an adult. Contrary to past research, IJA was not related to cooperative success. However, IJA was positively related to infants’ affiliative (*r*s(106) = .23, *p* = .018) and antagonistic behaviour (*r*s(100) = .23, *p* = .019) during cooperation. Infants who demonstrated more IJA in a non-cooperative task were more likely to produce affiliative and antagonistic behaviours in cooperative tasks. Surprisingly, negative relationships were found between cooperative success and affiliative (*r*s(166) = -.16, *p* = .044) and antagonistic (*r*s(166) = -.24, *p* = .002) behaviours, suggesting that infants successful at attaining shared goals were less likely to show affiliative and antagonistic behaviours while doing so. Our findings suggest that infants' IJA shapes the social context of cooperation and that affiliative and antagonistic behaviours may interfere with infants' cooperative success.