The President arrived at the polling station in Wilmington (Delaware) with his 18-year-old granddaughter Natalie, who is voting for the first time.
Biden's Democrats currently control both houses of Congress.
But polls show the Republican opposition is likely to regain control of both chambers amid widespread voter discontent over high inflation.
After the vote, Biden told reporters that he "feels good" and that the midterm elections were "not a referendum" but rather a "choice".
Biden said that it was a fundamental choice, a choice between two different views of the country.
The mid-term elections for Congress will be held on 8 November. They will elect all 435 members of the House of Representatives, also known as HOR, and a third of the senators. According to forecasts, Republicans could increase their representation in both houses of the legislature, giving them an opportunity to obstruct the implementation of the Democratic president's proposals.
Also, President Joe Biden commented on the incident that occurred with the husband of Nancy Patricia Pelosi.
The President has denounced the tense political climate in the USA.
He blamed former President Donald Trump and his followers' false claims that the last election was stolen.
"It is one thing to condemn violence," Biden said. "But you can't condemn violence if you don't condemn the people who keep claiming that the election wasn't real, that it was stolen."
The intruder at Pelosi's home, identified by police as a 42-year-old man, broke his skull but intended to target the speaker herself.
Pelosi, who as speaker of the House of Representatives is second in line to become US president, was not at home at the time of this morning's attack.
However, US House Speaker Nancy Pelosi said her husband Paul's condition was improving after the attack.
In a statement released Saturday on the website of the Speaker of the lower house of the US legislature, Pelosi thanked the law enforcement and first responders who responded to the attack on her husband. She also thanked the medics who treated her husband and noted that his condition "continues to improve".