The former First Lady added the president elect’s success over the weekend “isn’t a magic wand”. Her comments came following Mr Biden’s election victory over the weekend after he secured the necessary number of electoral votes required to beat current president Donald Trump.
In a speech on Saturday night in the US, the long-time Democrat vowed to “unify” the country after a year of political tensions.
Reaching out to supporters of his rival, Mr Biden added: “For all those of you who voted for President Trump, I understand the disappointment tonight.
“I’ve lost a couple of times myself. But now, let’s give each other a chance.”
In a series of tweets, Michelle Obama, wife of former Democrat president Barack Obama, highlighted the job that now lies ahead of Mr Biden.
She wrote: “After we celebrate – and we should all take a moment to exhale after everything we’ve been through – let’s remember that this is just a beginning.
“Voting in one election isn’t a magic wand, and neither is winning one.”
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She added: “We’ve also got to recognise that the path to progress will always be uphill. We’ll always have to scrape and crawl up toward that mountaintop.
“And two years from now, four years from now, there will once again be no margin for error.”
Indeed, supporters of Mr Trump have staged protests across the US following the election result last week.
Some have claimed the election result have been “stolen” following Mr Trump’s claims fraudulent votes were allowed to influence the outcome.
According to reports, many of the demonstrations involved around a few hundred people, though some were armed.
Meanwhile, Donald Trump’s campaign has claimed the president does not want to concede the election to Joe Biden, despite speculation over the past couple of days that he may do so.
Jason Miller, a senior campaign adviser for the president, told US news outlet Fox Business: “That word is not even in our vocabulary right now.”
The president has continued to claim there has been fraudulent or suspicious activity in states in which he lost to Joe Biden.
Just hours ago, he tweeted: “Pennsylvania prevented us from watching much of the ballot count. Unthinkable and illegal in this country.”
Before that, he said: “Nevada is turning out to be a cesspool of fake votes.”