Joe Biden took office as president of the United States on January 20, 2021, when he was inaugurated as the 46th president.

Since you asked this in a “Quick Scoop” style, here’s a compact breakdown.

Key date

  • Inauguration and start of term: January 20, 2021.
  • He completed his single term on January 20, 2025.

Very short timeline

  1. November 3, 2020 – Biden wins the presidential election against then‑president Donald Trump.
  1. January 6, 2021 – Attack on the U.S. Capitol; heightened security ahead of the inauguration.
  1. January 20, 2021 – Sworn in around late morning (about 11:49 a.m. EST) on the West Front of the Capitol.
  1. January 20, 2025 – His presidential tenure ends; Donald Trump is now president again after the 2024 election.

Forum-style context and “latest”

“So, when did Biden actually take office?”
He legally became president at noon on January 20, 2021, but he finished taking the oath a few minutes before that, which is why news coverage often quotes the late‑morning time of the ceremony.

As of early 2026, Biden is a former president; his administration is now discussed in past tense, including analyses of his term, his withdrawal from the 2024 race, and his farewell messaging.

TL;DR: Biden took office on January 20, 2021, served until January 20, 2025, and is now a former president.