Hermilo Argumedo bought the ticket at an Express Food Stop in Cypress, winning the second available top prize for the High Roller Casino Action game.
Odds of winning any prize in the game are one in 2.52, according to lottery officials.
Argumedo hasn't yet revealed how he will spend his $7.5 million, but a Texas Lottery representative said Argumedo plans to keep his post-winnings life private.
The store where Argumedo bought the ticket is also entitled to a $10,000 retailer bonus.
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