Magnetic fields are thought to govern the dynamics of protoplanetary disks by mediating inward gas accretion and, possibly, setting up turbulent concentrations of dust to form the first planetesimals.  A subset of these planetesimals then accrete to form rocky planets, which may eventually host magnetic core dynamos and mobile-lid plate tectonics.  I will present how recent advances in paleomagnetic instrumentation have enabled access to complex meteorites and early Earth rocks that record magnetic fields in the protoplanetary disk and on the early Earth and Mars. These studies support a central role for disk magnetic fields in planetary accretion, a long-lived core dynamo on Mars, and an early origin of mobile plate tectonics on Earth.