Filings with the SEC show he purchased more than 122,000 shares at $16.34 per share. It takes the total value of his investment in the company to just over $9m based on today's share price.
Kordestani, who used to be a top executive at Google, joined Twitter in October. It's Kordestani's first purchase of Twitter shares since joining.
Twitter finance chief Anthony Noto also splashed out $250k, buying up 15,500 shares at $16.08 per share. His stake in the company is valued at just over $22m.
Both executives are the first to increase their investment in the company this year at a time when the social network's share price hit rock bottom. Shares hit a nadir of $13.91 per share a week ago after reporting that user growth had stalled.
That took it to more than 45 per cent lower than its IPO price. It has since recovered somewhat, closing above $17 for the first time since the start of February yesterday.
Twitter revealed late on Friday evening that it will look at the way it's executives are rewarded after speaking to investors. It will award stock bonuses based on company performance, while Jack Dorsey will forgo "all forms of direct compensation".