I think you’re going to have a tough time with results for that phrase. If the negative information is not correct, you may be able to ask for it to be taken down (maybe threaten suing for defamation).
But if the information is correct, as desirable as it may to “wish it away as though it never happened” AFAIK there isn’t much you can do about it. If there were there would be a line of politicians in line in front of you.
I have removed the name from the topic title and your post. At the moment, a search for the name on Google brings up this thread near the top of the results. If you’re genuinely trying to remove negative results to create a better impression, then having the fact that that’s what you’re doing prominently displayed really seems to me like shooting yourself in the foot.
As the OP is no longer with us, I’ll answer that.
The negative link has moved up in Google and is now in first position. Bing now has two negative results on the first page, where previously there was only one.
It would appear that search engines are no more fooled than people are by the sudden creation of numerous social media profiles and blogs with little or no content, and some irrelevant name-dropping in posts. Creating fake accounts and keyword-stuffing posts with the name is not creating “positive” content.
I expect it would work eventually if you create genuine content of real interest. What seems to have been done in this case is little more than Spamming: accounts created on multiple social media and forum sites, with no further participation, and posts created by a third party with the name thrown in multiple times, completely irrelevantly. Also, blogs created with little or no content, or with plagiarised content.
IMHO, the overall impression you get of this person is worse now than before this misguided campaign began.