She has overcome many obstacles on the road to the nomination but they fade by comparison to the grit she’ll now need in the head-to- head battle against Republican nominee Donald Trump.
In case there was any doubt, Mr Trump set the tone over the weekend by pledging before his cheering supporters to “take the gloves off” against Ms Clinton.
Many analysts believe the electoral map favours Ms Clinton but underestimating Mr Trump would be disastrous for Democrats.
There is much that Ms Clinton must do if she is to successfully make her case over the next 100 days. Primarily, she must hone her message, stay on message, unify her party and get out the vote.
Her acceptance speech was solid, soaring, full of detail and even inspiring — but, apart from touting the historic nature of her candidacy and contrasting herself with Mr Trump, there was no one memorable line that defined both her candidacy and her primary goal as president.
Ironically, this is made more difficult by the fact that she has many goals: from improving education and healthcare to job creation, better wages and immigration reform.
In the weeks ahead or in the presidential debates, she may come up with a defining zinger but time is marching on.
By contrast, whatever one thinks of Mr Trump’s pledge to “make America great again,” the slogan has become a defining statement about his candidacy.
Ms Clinton’s task is made even more urgent because Republican opponents have already spent decades defining her in negative terms.
Ultimately, Mr Trump may be her best asset. All she has to do, some Democrats suggest, is to cast herself as the best of the American Dream to his American nightmare.
That will undoubtedly help. But while contrasting herself with her Republican rival may fire up her base, it will not be enough to win over wavering voters.
Her $275bn plan to generate thousands of jobs by rebuilding the country’s crumbling infrastructure is the message she must pound again and again.
“In my first 100 days, we will work with both parties to pass the biggest investment in new, good-paying jobs since World War II,” she declared at the convention.
“Jobs in manufacturing, clean energy, technology and innovation, small business, and infrastructure.”
Mr Trump, too, has a plan. He wants to build “ the greatest infrastructure on the planet earth” but, unlike Ms Clinton, he hasn’t laid out how he’d do it.
The recession and the outsourcing of jobs have eviscerated families, especially across the forgotten states of Middle America. Mr Trump has won them over by stoking their fears and offering them scapegoats.
Ms Clinton must now win them back with a message about what her one-time rival Bernie Sanders might call a “jobs revolution”.
Of all the speeches at the Democratic convention, the most important may well turn out to be that made by the Democrat-turned- Republican- turned-Independent former New York Mayor Michael Bloomberg.
He pummeled Trump, talked up Clinton and urged Independents, as well as Republicans who oppose Mr Trump, to vote for Ms Clinton.
Now she needs to build on that. She needs to aim her message at wavering Independents and “Reagan Democrats”—those conservative Democrats who voted for Republican Ronald Reagan over Democrat Jimmy Carter in 1980.
It’s time for her to stop worrying about Mr Sanders’ followers on the left because he’s made sure she’s going to win enough of them. She must now ensure “Reagan Democrats” don’t become “Trump Democrats”.
To win them over she could draw on her New York senate strategy. When she originally ran for the New York senate seat 16 years ago, polls showed most New Yorkers neither liked nor trusted her. So she went all across the state on “listening tours” to win them over. It worked. She was elected in 2000 and re-elected in 2006.
“Listening tours” across 50 states would certainly pose a much bigger challenge but she could tap her vast social media network for “virtual listening tours”.
Above all, she must keep her cool on the campaign and especially in the coming presidential debates. To paraphrase a line from first lady Michelle Obama’s convention speech: “When Mr Trump goes low, Ms Clinton must go high”.