On Monday, Bill Bolling held a part-time, largely ceremonial post that paid him $36,000 a year.

On Tuesday, Bolling’s job became one of the most important in the state.

Virginia’s GOP lieutenant governor is the reason his party will lead the state Senate after last week’s elections left the chamber evenly split between Republican and Democratic legislators.

Bolling will wield the gavel in the Senate and cast the deciding ballot in any tie, and it is that power that will give Republicans control of the chamber’s floor sessions, committees and bills.

“He’s the most powerful man in Virginia,’’ Gov. Robert F. McDonnell (R) quipped at a news conference last week.

And the state’s Republicans are now in a remarkably powerful position. For only the second time since the Civil War, Republicans now control both chambers of the General Assembly and the governor’s mansion.

In an interview, Bolling credited his party’s focus on results with its showing in the election. “If we do that effectively, then the environment will stay positive,” he said. “But if we don’t . . . the pendulum could swing back to the other side just as quickly.’’

Bolling, an insurance executive with a Southern twang, has made no secret of his desire to succeed McDonnell in 2014. His elevated role could help those aspirations but could hurt them, too. Certainly, it will raise Bollings’s profile — and perhaps take him out of the shadow of Attorney General Ken Cuccinelli II (R) — but the bigger platform and the decisive role in key Senate votes could make him a target, as well.

“It’s good and bad,’’ said Anthony Bedell, chairman of the Fairfax County Republican Committee. “The good is he’s going to have a higher profile. The bad is he’s going to have a higher profile.’’

May face some hard votes

First elected when Democrat Timothy M. Kaine won the governorship in 2005, Bolling was reelected to the No. 2 job in 2009, alongside McDonnell, who was elected governor.

Since then, Bolling, 54, has been a key adviser and emissary for McDonnell, serving as the state’s chief jobs creation officer and stressing kitchen-table issues, including the economy, transportation and higher education.

The legislature’s new Republican majority will undoubtedly help the administration pass proposals but will also force Bolling to take sides on hot-button issues, such as gun rights, immigration and abortion — issues Bolling has largely sidestepped but will be pushed on by a growing conservative faction of the party.

“As a tie breaker, he may have to take some hard votes,’’ said House Minority Leader Ward L. Armstrong, a Democrat from Southside who is considering a run for governor in 2013. “It will strengthen him for the nomination, but it will make it harder in a general election.’’

Bolling, a self-described fiscal and social conservative, dismissed any pressure in casting controversial votes, and he said Republicans would continue to work on the same issues they have been, primarily relating to the economy.

“Our focus is going to remain fixed on the core issues that the people of Virginia care about,’’ Bolling said. “We will just have to deal with other initiatives that might come out of the legislature on a case-by-case basis.’’

After decades of Democratic control, the chamber split evenly in 1996. Democrats, who had 20 senators plus the lieutenant governor, intended to control the chamber. But Sen. Virgil Goode, a Democrat who later switched parties while serving in Congress, would not agree to the reorganization unless Republicans were allowed to share power in the chamber. The two parties shared control for four years.

Don Beyer, the Democratic lieutenant governor during those years, said he estimates that he cast more tie-breaking votes than every other lieutenant governor combined. But many votes, he said, were on procedural issues and even those that were contentious were split not on party lines, but on cultural or geographical divisions. Only one vote — about whether welfare recipients could appeal the state’s decision — was used against him in his unsuccessful run for governor in 1997.

Beyer, now U.S. ambassador to Switzerland and Liechtenstein, said in an interview that Bolling will get more attention but that any future races will probably be decided on other issues. “It does make him more a player,’’ he said. “But in general, it’s going to be overstated.’’

In 2000, Republicans took full control of the chamber. In 2007, Democrats rode a national anti-Republican wave and flipped it back.

After the election last week, Democrats waited nervously for Republicans to decide whether they would allow the parties to share power. But on Wednesday, after the numbers for the final race became clear, the GOP immediately asserted its power.

While McDonnell sounded conciliatory, telling Republicans not to be arrogant and Democrats not to be angry, Bolling delivered a strong statement about the GOP’s decision to exert control over the chamber. He said later that Republican leaders decided before the Capitol Square news conference that he would be the one to carry that message. “That’s my role,’’ he said.

Republican senators will meet this week to chose their caucus’s leaders — and begin to ponder chair leaders for committees — as they ready for the 60-day session that begins in January.

Sen. John C. Watkins (R-Chesterfield), easily reelected last week, said he hopes Bolling doesn’t encroach on the prerogatives of the legislature by acting like the 21st GOP senator.

“I hope he sticks to his word and doesn’t try to leverage his position,’’ he said.

The 2013 gubernatorial race

Bolling grew up in coal country in Virginia and West Virginia. He was the first person in his family to graduate from college. The vice president of one of the nation’s largest independent insurance brokers, he lives outside Richmond with his wife, Jean Ann.

He spends a couple mornings a week at his insurance office and 40-plus hours working for the state — talking to business executives, cutting the ribbons on new businesses and attending meetings of some of the eight government boards he serves on.

Bolling, a former state senator from Hanover County, said he spent four years as lieutenant governor “on the outside looking in “ during Kaine’s administration. He was expected to run for governor in 2009, but he instead ran for reelection as part of a team with McDonnell.

McDonnell, one of the most popular governors in the nation, has given him an elevated role as a member of his Cabinet and is supporting him in the 2013 gubernatorial race.

Terry McAuliffe, an unsuccessful gubernatorial candidate in 2009, is the only other candidate who has told people he expects to run for governor. The former head of the Democratic National Committee campaigned for candidates across the state this year, but declined to comment on his party’s losses or Bolling’s new role.

Cuccinelli, a tea party favorite who was elected as part of a GOP sweep in 2009, has said he is weighing whether to challenge Bolling in a primary in 2013 or U.S. Sen. Mark Warner (D) in 2014.

Gary C. Byler, a longtime Republican activist who chairs the Second Congressional Republican Committee, called Bolling a “statesman” for allowing McDonnell to run unopposed in 2009, but said he expects a member of his party to challenge him in 2013.

“It reflects a general dissatisfaction with the nomination being inherited,’’ he said. “It needs to be earned in its own right.”