Hilton, the prime minister's former closest adviser, left Downing Street in 2012 to take up a teaching post at Stanford University in Columbia. He has been informally advising the prime minister, according to reports, and made a tentative return last year as an unpaid member of Cameron's Conservative Parliamentary advisory board.
"There's a lot of concern about the way that big money donors and special interests seem to be taking over the system," he told MSNC's Daily Rundown programme on Tuesday evening.
He went on: "Don't just vote, donate, because if you want to shape the next Congress, for many people their vote actually isn't the most powerful way they can do that, the most powerful way they can do that is donate to the campaigns that match their priorities."
Hilton made the comments as he promoted his new business, CrowdPAC, which offers voters a chance to fund the candidates who most closely match their priorities.
Labour MP Sheila Gilmore told the Huffington Post UK: "This confirms what we knew already: David Cameron's government stands up for the privileged few because his campaign relies on their funding.
"The Conservative Party are increasingly reliant on a small pool of big money donors, including hedge funds and secretive associations. They are a hollowed out party in hoc to vested interests, as David Cameron's former guru has just made clear."
Hilton defended himself from accusations he thought voting didn't matter, stressing that the "best way to fight big money is more small donors".