Gates is believed to be the only other person to reach $100 billion in 1999.
It came as sales over the internet overall shot up by almost a fifth (18.4%) on the day - as shoppers snapped up bargains - compared to the same 24-hour period previous year, figures show.
Bezos officially earned the title in October when he surpassed Gates, a feat he also briefly accomplished in July. The last billionaire to do so was Microsoft co-founder Bill Gates. Bezos' fortune now sits at $100.3 billion, up $2.4 billion following a 2 percent increase in Amazon's shares.
Bezos started 2017 as the fourth richest person in the world, and surpassed both Inditex (ZTSTF, +2.98%) founder Amancio Ortega and Berkshire Hathaway's Warren Buffet this year as well.
Now, as online shoppers gear up for the holidays with some sweet Black Friday deals, Bezos has regained the top spot and skyrocketed past the coveted $100 billion mark. Unlike Gates, Bezos has given very little of his fortune to charity so far. That stake alone is worth more than $93.5 billion as of Friday's closing price of $1,186 a share.
The hike in Mr Bezos's wealth had soared by $32.6bn this year up until Thursday, with the extra $2.4bn landing in his pocket ahead of the consumer frenzy, and secures his position as the world's richest man. In June, he tweeted a solicitation for ideas on a philanthropy strategy. After the close of trading in NY on Friday, the billionaire's total net worth fell back down to $97.9 billion.
His goal was to tackle problems "at the intersection of urgent need and lasting impact".