How does political ambition affect strategies of cooperation in Congress? What activities do legislators develop with their peers to maximize their career goals? One of the main collaborative activities in a legislature, cosponsorship, has been widely analyzed in the literature as a position taking device. However, most findings have been restricted to environments where ambition is static (i.e., legislators pursuing permanent reelection), which restricts de facto the variety of causes and implications of legislative cooperation. I analyze patterns of cosponsorship as a function of ambition in a multilevel setting where legislators praise subnational executive positions more than a seat in the House. Through the analysis of about 48,000 bills introduced in the Argentine Congress between 1983 and 2007 and the development of a map of political careers, I follow a social networks approach to unfold different patterns of legislative cooperation. Findings show that patterns of cooperation among prospective gubernatorial candidates are strongly positive, while similar effects are not observed at the municipal level.