The phrase "worthy ambassador" refers to a person who is a good representative or spokesperson for a particular cause, organization, or country. Full definition
And that game gave us Mertesacker and Arteta who have been largely worthy ambassadors for Arsenal (justarsenal.com)
Meyers seemed to know that he maybe wasn't the most worthy ambassador for the community just now, but there was also something smug in that knowing. (vanityfair.com)