Biden's nominee for surgeon general, Dr. Vivek Murthy, who served in the same role in Obama administration, reminded in his remarks that COVID-19 is not the only health crisis devastating families and shortening life spans in America while warning that even with the best policies, the nation must overcome the fear and distrust that many are feeling amid the pandemic.

"In my new expanded role, I will work to bring a health focus to our policies across government so that our schools, our workplaces and our communities can be forces for strengthening our health and wellbeing, but the truth is that the very best policies, and even the best vaccines and treatments, will not heal our nation unless we also overcome the fear, anxiety, anger and distrust that so many Americans are feeling right now," Murthy said.

"So more than anything, I will come to this role as a doctor, one who learned the most important lessons about medicine not in medical school, but from the clinic that my parents opened when they first came to America as immigrants decades ago," he added.

Drawing from personal experience, Murthy went on to say he is "endlessly grateful to serve one of the few countries in the world where the grandson of a poor farmer in India could be asked by the president-elect to look out for the health of an entire nation."

California Attorney General Xavier Becerra, Biden's nominee to lead the Health and Human Services Department who would be the first Latino in the position if confirmed, said the incoming Biden administration will elevate the knowledge of medial professionals and build a country where health care is a right, not a privilege.

"At HHS, tackling pandemics, saving lives, keeping us healthy, should be our calling card. And we won't forget that there is a second "H" in HHS, the human services: the work we do for our children, the seniors and and disabled. They will stand tall in a Biden-Harris HHS," Becerra said.

Becerra also shared a personal story, of his father passing away peacefully at home on New Year's Day, contrasting it to the present moment.

"No one should ever have to die alone in a hospital bed, loved ones forced to stay away. That seems so contrary to the values of a great nation, the values that drew my parents like generations before and after them to come to America," he said.

Becerra led the states' defense of the Affordable Care Act after the Trump administration sued to dismantle the program earlier this year.

Ahead of introducing his health care picks, Biden made his mask campaign official and called on all Americans to wear a mask for the first 100 days of his presidency as part of three key objectives he's asking his health care team to complete in his first 100 days in office.

"My first 100 days won’t end the COVID-19 virus. I can't promise that," Biden said. "We didn’t get into this mess quickly. We're not going to get out of it quickly. It's going to take some time. But I'm absolutely convinced that in 100 days we can change the course of the disease and change life in America for the better."

Biden said his team's second initiative is to have "at least 100 million COVID vaccine shots into the arms of the American people in the first 100 days." The initiative comes as the Biden team has said it's seen "no detailed plan" on vaccine distribution from the Trump administration.

Finally, Biden said getting children back to school and keeping them in school will be a "national priority" for the team in the first 100 days, saying Congress can help make this happen with the appropriate funding.

"I'm encouraged by the bipartisan efforts in Congress around a $900 billion economic relief package which I've said is critical, but this package is only a start for more action early next year," Biden added.

Biden is introducing a slate of health care experts and officials who will lead his administration's response to the ongoing COVID-19 crisis.

"Today, I’m very proud to be announcing our health care and COVID team at a critical time, as we near the end of one of the toughest years we've faced as a nation," Biden said, adding this group of "world class experts" will be "ready on day one."

California attorney general and former California congressman, Xavier Becerra, is Biden's nominee for secretary of Health and Human Services. If confirmed, he would be the first Latino to lead the department.

Vivek Muthy has been nominated to be U.S. surgeon general, a role he served in during the Obama administration.

Dr. Rochelle Walensky, a leading expert on virus testing, prevention and treatment, is nominated to serve as director of the Centers for Disease Control and Prevention.

Dr. Marcella Nunez-Smith, one of the country’s foremost experts on health care disparities, will serve as the COVID-19 equity task force chair.

As Biden said last week, Dr. Anthony Fauci will stay on in his current role as as director of the National Institute of Allergy and Infectious Diseases and will take on the elevated role of Biden's chief medical adviser on the COVID-19 pandemic.

Jeff Zients will serve as coordinator of the COVID-19 response and counselor to the president, and Natalie Quillian will serve as deputy coordinator of the COVID-19 response.

While the U.S. Supreme Court has twice refused to hear pro-Trump challenges to the 2020 elections, a federal judge in Wisconsin on Saturday joined the chorus of rulings against Trump in his effort to use the courts to invalidate Biden’s victory.

“This Court has allowed plaintiff the chance to make his case and he has lost on the merits,” wrote U.S. District Court Judge Brett H. Ludwig, a Trump appointee. Ludwig noted that the president had asked “that the Rule of Law be followed,” and he declared in response: “It has been.”

The ruling comes just one day after the U.S. Supreme Court refused to consider an election challenge brought by the Texas attorney general contesting the way elections were run in four states, including Wisconsin. Trump had called that case “the big one,” because he thought it held the best hopes for him of re-litigating the 2020 contest in court.

This latest ruling marks nearly 50 losses for the president  in cases brought by him and his supporters since election day. In Wisconsin, where Biden won by more than 20,000 votes, Trump asked for 221,000 absentee and mail-in ballots to be excluded on the grounds they were collected in ways not laid out by the state legislature. And the president argued that the legislature should be afforded the chance to select an alternate slate of electors.

Ludwig’s 23-page opinion gave wide latitude to Trump -- finding that the president had standing to file his election challenge and was not too late to raise his concerns about the way the election was conducted. But the outcome of the case was the same as rulings in other battleground states -- that Biden’s victory was attained legally and should not be thrown to a legislature to upend.

The president, Ludwig wrote, “has not proved” that state election officials violated his rights. “To the contrary, the record shows Wisconsin’s Presidential Electors are being determined in the very manner directed by the Legislature, as required by Article II, Section 1 of the Constitution.”

Ludwig further noted that if he followed the demands set out in Trump’s lawsuit, “any disappointed loser in a Presidential election, able to hire a team of clever lawyers, could flag claimed deviations from the election rules and cast doubt on the election results. This would risk turning every Presidential election into a federal court lawsuit over the Electors Clause.”

The Trump campaign has not yet responded to requests for comment.

At the moment the federal ruling was handed down, the Wisconsin Supreme Court was hearing arguments on a separate challenge to a recount of votes in the state, which had failed in a lower court.

-ABC News' Matthew Mosk and Alex Hosenball