It's certainly a good place to start and anything is better than nothing. Take things easy to start with if you're really unfit and slowly build up speed. I walk to the railway station each morning to get to work and comfortably cover 2 miles in just under 30 minutes. Do that again in the evening, plus whatever you do just going about your normal business during the day, and it's surprising how far you actually cover.
The next step up (pardon the terrible pun here) is to use the stairs more. If you use a lift (elevator) at work, get out a floor early and walk up the rest until you eventually walk up all the way. Again build slowly and your level of fitness will rise. I'm 3 months into the paleo lifestyle and now run up and down over 120 stairs every working day (sometimes more than once).
Apart from that, the only exercise I get are a few (and I mean only a handful) of air-squats, sit-ups, push-ups and a plank. Oh, and running around after the family and running a Scout group.