If you share a name with someone who has an awful online reputation, their negative Google results can be just as big a problem for you. The best way to separate yourself from your digital doppelganger is to focus on proactively building your online reputation. Sign up for LinkedIn, Twitter and other social networking websites that have a place for a professional biography. Use these bios to tout your professional expertise and separate yourself from the person who shares your name.
You should also consider differentiating your name in some way, like using your middle initial or a nickname.