It's not that easy.
"It's rhetorical only," said Robert Bixby, a veteran Washington player and executive director of the Concord Coalition, a budget group, about the promise of the first day. "It takes time to make serious change."
In his first television ad of the general election campaign, which ran beginning May 18 in swing states including North Carolina, Ohio and Virginia, Romney promised he'd start working on tax cuts, changes in federal health-care laws and approval of the Keystone XL oil pipeline.
"Day One," said another ad, "President Romney announces deficit reductions, ending the Obama era of big government, helping secure our kids' futures."
"What will be different about a Romney presidency?" asked the newest ad Friday. "From Day One, President Romney focuses on the economy and the deficit, unleashes America's energy resources, and stands up to China on trade. President Romney's leadership puts jobs first."
Romney also plans to send legislation to Congress containing tax proposals and an immediate 5 percent cut in non-security discretionary spending, which includes programs such as education and transportation.
But those plans, like others in his Day One agenda, face obstacles every modern president has endured.
First, he's probably not going to have a lot of top staff in place. Cabinet secretaries and key trade and economic officials will need Senate confirmation. The campaign maintains it can take some action without all staff in place, such as designating a country as a currency manipulator.
Second, regulations and laws often can't be eradicated overnight. Repealing the 2010 health-care law, for instance, would require an act of Congress.
Romney has said he would issue an order "paving the way" for the government to issue state waivers to allow states to "innovate and design health-care systems that work best for them."
Complete repeal would be considerably tougher. Republicans now control the House of Representatives, and if they retain their majority, repeal could come on that first day, if not sooner. But any such effort would need 60 votes in the Senate to overcome a likely Democratic filibuster.
Third, while Romney can offer a detailed budget and tax plan on Day One, it often takes weeks if not months to get legislation through Congress.
Obama was elected in 2008 on a similar promise of dramatic change. On Day One, he held a signing ceremony and signed executive orders that included placing restrictions on lobbyists and pledging government transparency.
A day later, he signed an executive order to close the detention facility for suspected terrorists at the U.S. naval base at Guantanamo Bay, Cuba.
The administration met vociferous opposition in Congress to its Guantanamo plan. The detention facility remains open.
The administration also pulled back on the restriction aimed at closing what Obama called a "revolving door" of lobbyist influence in government. The executive order he signed included a waiver, which the administration soon employed to secure the appointment of a deputy defense secretary.