A player in Southsea matched five numbers in the draw on Saturday 5 August. As a result they will take home £2,000, the second largest prize available in the draw.
The winner, who prefers to remain anonymous, said "I signed up for The Portsmouth Lottery to support our lovely city.
"An added bonus, for me, was part of your stake going to a good cause of your choice and part put into our city. I chose the RSPCA Solent Branch as animal rescue is a cause close to my heart.
"It was a wonderful surprise to win and I will be using the money to donate to other charities I support and having fun with the family with the rest!
"I'll definitely continue to support our lottery. Thank you!"
Since the first draw on 5 November 2016, there have been 2055 winners - who have banked a share of £16,152 in prize money and free entries.
"I'd like to offer congratulations to our first big winner" said Cllr Luke Stubbs, council's Cabinet Member for Health and Social Care and panel member for the Portsmouth Lottery small grants fund.
"The lottery is making a real impact in the voluntary and community sector through ticket sales and the small grants we've awarded so far. I'd encourage good causes in the city to find out how they can get involved."
The Portsmouth Lottery benefits local charities, not-for-profits and good causes in the city. 60p of every £1 ticket goes to good causes making a difference to Portsmouth people.
There's still time to get tickets for this week's draw - in which you could win £25,000. Visit www.portsmouthlottery.co.uk before midnight on Friday 11 August to register.