In 2013 California adopted a new watershed state finance policy, the Local Control Funding Formula (LCFF) to drive more resources to students with higher needs, create more spending flexibility, and let districts decide how to spend substantial new dollars. Our analysis examines financial data from nearly all California school systems to clarify how their spending choices changed in the first three years of the new state funding law. We find that predictions of wholesale ill-conceived spending choices in the absence of state prescription have not been borne out. And while we find that districts generally didn't make radical changes in spending, they did spend in ways that could help the highest-need students and did show evidence of "customizing" spending to meet local needs. With LCFF, California has undertaken one of the nation's largest weighted student funding (WSF) overhauls to date. As such, its experience is of national interest. This paper is part 1 of a series analyzing early impacts of LCFF. [For part 2, see ED612170. For part 3, see ED612172.]