Don't write your LinkedIn summary in the 3rd person. Just don't do it. At best it reads like you are too busy to write one yourself and had your assistant do it, and at worst it just makes you sound like a pompous jackass.
You could go the over-the-top route and just write a bombastic self-deprecating 3rd person summary, but in my opinion they are very hard to pull off. When Sam Zell was bringing in his management team at Tribune, several had these type announcements, or 'press releases' I think is what they called them. The first time you saw it, you were amused. By the third one, it just felt like a two paragraph dick joke. But a lot of those guys were shock jocks, so it made sense for them I guess. I advise against it.
7 Reasons to Put Your LinkedIn Profile in 1st Person And Not 3rd Person
Executives: Don’t Make These 4 LinkedIn Mistakes