As said, there's EAGLE for Mac, but the interface is horrible (on any platform), and it doesn't fit in with system shortcuts like a program should. I've designed a handful of boards in it, and there is good community support for libraries - SparkFun, for example, make lots of EAGLE parts.
Virtualbox is an option, either to run Windows (ugh) or Linux (most distros are relatively lightweight, should boot fast and run well under virtualisation).
- KiCAD is a popular FOSS program for Windows and Linux (don't bother trying on Mac, it's too experimental), but it shares the same horrid UI ideas as EAGLE, such as adding extra button clicks to do simple things, like moving a component. Such unintuitive UI is generally defended with the usual cop-out excuse of "learning curve". But hey, it's free, and it's considered very good.
- Altium has a fantastic user interface, which obeys UI conventions that we have grown into over the past 20 years. It's Windows-only, and a commercial program, so it costs money to (legally) obtain.