Honestly, yes.
As well as knowledge of vSphere itself, you would also benefit from knowledge and experience in server operating systems and applications, networking (eg. switches, routing), shared storage (eg. SAN/NAS).
I would suggest using VMware Player or Workstation to get started with virtualisation, then when you're ready to start using vSphere there's a ton of resources here: Download VMware vSphere with Operations Management Evaluation - Free Managed Virtualization for 60 Days