The Mathematics Teacher Education Partnership (MTE-Partnership) was formed to address the undersupply of new secondary mathematics teachers who are well prepared to help their students attain the goals of the Common Core State Standards and other college- and career-ready standards. This national consortium of more than 90 universities and 100 school systems has been organized as a Networked Improvement Community (NIC), which combines the disciplined inquiry of improvement science with the power of networking to accelerate improvement by engaging a broad set of participants. Initiating a NIC involves a number of challenges described in the NIC Initiation Framework. This case study analyzes the MTE-Partnership's progress in one domain of that framework: network leadership, organization, and operation. Areas of discussion include convening the network, establishing a membership framework and participation structures, building leadership and hub functions, developing a communications infrastructure, and finding necessary resources.