Peter Howes, 58, of Waterlooville, Hampshire, submitted fraudulent VAT returns to HMRC between June 2011 and October 2017.
He claimed he was working as a builder and entitled to VAT repayments on his taxable purchases.
But investigators found Howes hadn’t been working and had simply made up the figures on his VAT returns.
Richard Wilkinson, Assistant Director, Fraud Investigation Service, HMRC, said: “Howes committed VAT fraud to fund his gambling habit, and is now in jail for his crime.
“He stopped working as a builder and used the tax system as his personal bank account. It is simply not acceptable to steal from UK taxpayers and the public services we all rely upon.
Howes fraudulently claimed £750,602 under his former trading name of P D Howes Building and Development.
He received around £9,500 each month, and spent the money on gambling and his general lifestyle. HMRC withheld £19,875 of the money claimed while investigations took place.
At Portsmouth Crown Court, Howes pleaded guilty to the fraudulent evasion of VAT and was jailed for two years and eight months.