Almost 33.8 million people watched Mr Biden’s six-hour-long inauguration ceremony over 17 television networks on 20 January, said Nielsen.
While Barack Obama’s first inaugural in 2009 drew 37.8 million viewers, Ronald Reagan’s popularity peaked to 41.8 million in 1981.
Mr Biden also exceeded viewership of his predecessor Donald Trump, who watched the television ratings actively and closely. Nearly 30.6 million people watched Mr Trump take the oath of office in 2017, according to Nielsen.
The 78-year-old became the oldest person to serve the nation as US president, issuing a call for unity in his speech. The ceremony included the performances by Lady Gaga, Jennifer Lopez and Garth Brooks. Kamala Harris, who was a former senator, became the first Black person, first woman and first Asian-American to serve as vice president.
Meanwhile, CNN became the most popular network among the viewers for inaugural ceremony.
Contrary to Nielson’s ratings, right wing channel Fox News projected that the viewership of Mr Biden’s inauguration ceremony was down to 77 per cent from the channel’s viewership for Mr Trump.
The new president also has favourable job approval rating in early polls at 63 per cent among registered voters.
After being sworn–in as president, Mr Biden passed at least 17 executive orders as part of a range of his new domestic and international policies during the first 24 hours of his presidency.
He ended Trump administration’s travel restrictions on several Muslim majority countries and halted the construction work along the US-Mexico border, among other decisions.
Mr Biden also began talks with Congress over a $1.9 trillion stimulus package to provide relief to those most impacted by the pandemic.