Does doing a postdoc mean a commitment to an academic career?
Well, clearly, it depends on many factors (my answer is probably strongly influenced by the Computer Science field). 


If you want to apply for a non-research industry position, then clearly, the postdoc might not appear as a strong point, unless you can travel, attend conferences, manage a budget, develop an application/software/experiment, apply for patents, etc, in general any transversal skill that you can justify. But if the postdoc is just sitting in an office writing theoretical papers for a couple of years, then it's probably not the best choice. 
If you want to apply for a research industry position, then a postdoc can be a good point, although of course, the closer you can be connected to industry, the better it will be. 
Ideally, you could do a postdoc in industry (in CS, IBM, Microsoft, Intel, HP, and many others offer this possibility).