Season One: The Great Beginning

Jack's Big Brother One: The Great Beginning began on March 29, 2021 and ended on April 27, 2021. The season featured 12 contestants fighting to be the first winner. On Day 30 after a month long battle, Julia became the winner up against Dallas in a 7-0 vote.

Houseguests
See Main Article: List of JBB Houseguests The entire cast was revealed on March 29, 2021 shortly before the premiere.

Twists
The season featured various twists throughout the season.

In Week 1, the three lowest placing members in the HOH comp became Have-Nots.

In Week 5, a surprise Battle Back competition took place, in which Nick won.

In Week 6, two HOHs were crowned instead of the usual two. This was won by Dazed and Nick.