In the years before he lost his Pennsylvania Senate seat in 2006, Rick Santorum worked hard to win hundreds of millions of dollars in additional Medicare money for hospitals in Puerto Rico.

He sponsored at least two Senate bills and pushed to amend a mammoth Medicare overhaul to include the extra spending, which would have benefited Universal Health Services, a Pennsylvania-based hospital management company with facilities in Puerto Rico. If it seems at odds with the small-government philosophy Mr. Santorum now espouses in his presidential campaign, it was in line with his legislative efforts to help businesses in his state.

And some of those businesses were happy to return the favor.

Within months of leaving the Senate, Mr. Santorum joined the board of Universal Health Services, where he collected $395,000 in director’s fees and stock options before resigning last year. He also became a consultant to Consol Energy, after years of advocating drilling and extraction policies helpful to the company, a Pennsylvania gas and coal producer. And he consulted for the American Continental Group, a lobbying firm whose clients won earmarks he sponsored.

As Mr. Santorum’s standing in the race for the Republican presidential nomination has been energized by his strong showing in the Iowa caucus, so too has the scrutiny of his activities since leaving the Senate. When he left office he was not especially wealthy, but records show he wasted little time fashioning a lucrative post-government career based largely on income from businesses that had benefited from his work in Congress.