That implementation often distorts political intentions as they are translated from goals to policy is one general finding of implementation research. However, how implementation are affected by current administration demands to strengthen horizontal coordination in government through the use of softer governance tools is less researched. This trend is mostly understood as part of a “post-new public management” in reaction to the “one-silo” administrative structures of early new public management. I present original data from a total sample of central agencies in Sweden on the implementation of a crosscutting issue: gender mainstreaming. I examine how three theoretically distinct tools of government, i.e., steering, leadership, and knowledge/resources, contribute to successful implementation. The analysis uses subjective assessment of success and tool-use from personnel in leading positions from a total sample of central Swedish agencies. The analysis demonstrates that leadership support is the only significant factor contributing positively to gender mainstreaming success.