The 23-year-old has become the Owls' third signing of the close season following the addition of defender Chey Dunkley and forward Fisayo Dele-Bashiru is back on familiar territory in the White Rose county.
He has joined the club on a season-long loan.
Brown was a leading light in Huddersfield Town's promotion line-up of 2016-17, playing an integral role in the second half of the season with some valuable contributions.
The Peterborough-born player had spent the first half of that season on loan at Rotherham United before his spell was cut short by Chelsea so that he could be loaned back out to the Terriers.
Brown's career has faltered in the past few seasons, having endured an injury-hit season-long loan at Leeds United in 2018-19, which saw him make just two appearances, with head coach Marcelo Bielsa expressing regret that the talented midfielder could not achieve full fitness in a luckless spell.
Injury issues also hampered him for spells during a season-long loan at Luton Town last term, with Brown aiming to rewind the clock to happier times in Yorkshire, more especially with Huddersfield.