WASHINGTON – Republican presidential candidate Rick Santorum released four years of federal income tax returns on Wednesday night, showing a sharp rise in his personal wealth spurred by his growing work as a Washington-based corporate consultant and media commentator.

Santorum, 53, has sold himself in the Republican primaries as both a social conservative and a Washington outsider, stressing his family’s coal-mining background and his appeal to religious and working-class voters.

His personal finances tell a different story, detailing the trajectory of a politician who grew more prosperous in the Senate and became a millionaire afterward, at times capitalizing on his Beltway connections.

The former Pennsylvania senator’s tax returns show his annual income surged from nearly $660,000 in 2007 to $1.1 million in 2009 before slipping to $923,000 in 2010.

Santorum’s wealth doesn’t come close to the multimillion-dollar fortune amassed by Mitt Romney’s high-finance prowess or Newt Gingrich’s smaller but still-lucrative blend of foundation and consulting work.

But his new-found affluence reflects his close ties to Washington’s business and lobbying circles during his 12 years in the Senate and his smooth transition into their world after he left office.

His federal income taxes rose from 2007, when he paid $167,000, to $310,000 in 2009, then dropped to $263,000 in 2010. Santorum paid a combined tax rate of 28 percent during the four years, putting him in a high tax bracket but not in the top 35 percent.

Gingrich paid an estimated 31 percent, according to his federal returns, while Romney paid 14 percent because many of his earnings came from investments taxed at a lower capital gains rate. Both Romney and Gingrich recently disclosed income tax returns.

Santorum’s 2010 tax returns show he made more than $550,000 in media and consulting fees – paid to him through a corporation he set up, Excelsior LLC. The previous year, Santorum made more than $820,000 in fees, also paid through the same firm.

Last year, Santorum disclosed investment and real estate assets totaling as much as $2.5 million. In his presidential financial disclosure spanning 18 months between 2010 and 2011, Santorum also listed $1.3 million in income as a consultant – much of it coming from media appearances and corporate work on behalf of health care, energy and social conservative interests.

Santorum and his wife, Karen, took standard deductions each year for their seven children, the returns show.

In 2007, the Santorums took a $4,000 charity deduction for giving away “clothing, footwear, accessories and household items.” That year, the family moved into a larger home in the Virginia suburbs of Washington.

Santorum and his family now live in a four-bedroom northern Virginia house on five acres assessed at $1.4 million in 2010.

The tax returns were first made available Wednesday night by Politico.