Tan Nguyen, a Republican who was running for Congress in Orange County, will also serve six months in a residential re-entry program and three years of supervised release, federal prosecutor Greg Staples said.
Nguyen declined to comment on the hearing before U.S. District Court Judge David O. Carter except to say it didn't go well.
He will start serving his term March 28.
A jury convicted Nguyen in December of one count of obstruction of justice for lying to state investigators about his knowledge of a letter sent to 14,000 registered Democrats with Latino surnames during his bid to unseat Democratic Rep. Loretta Sanchez in 2006.
The letter, written in Spanish, said: "You are advised that if your residence in this country is illegal or you are an immigrant, voting in a federal election is a crime that could result in jail time."
Immigrants who have become naturalized U.S. citizens are eligible to vote.
During the trial, prosecutors accused Nguyen of being behind the mailer, while his defense attorney argued that Nguyen saw an initial English draft of the text but had nothing more to do with it.
"Mr. Nguyen's conduct undermined the public's expectation of honesty from public officials and those who desire to serve," U.S. Attorney André Birotte Jr. said in a statement Monday.
The California attorney general's office, which investigated the letter, did not file criminal charges against Nguyen.
Defense attorney Dean Steward said that should have been the end of the probe. He questioned the federal government's interest in the case.
"Why is the FBI sticking their nose into it?" Steward said after sentencing. He said Nguyen will appeal his conviction.
The controversy about the letter erupted three weeks before the Nov. 2, 2006, election. Sanchez beat Nguyen by nearly 24 percentage points to earn her sixth term representing the central Orange County district, which is home to sizable Latino and Vietnamese-American communities.