Brownhill, 24, worked his way through the Red Devils’ youth ranks before being released at the age of 16 in 2012.
He was swiftly snapped up by Preston North End before moving to Ashton Gate four years later.
Brownhill has emerged as a key figure in Lee Johnson’s team and he cannot wait to test himself in tomorrow’s Carabao Cup quarter-final clash against United (8pm).
“I was at Manchester United from the age of six, and got released just before a scholarship,” he told EFL.com.
“I have really fond memories of my time there and made some great mates along the way, who I still keep in touch with.
“At the time, getting released was horrible. Especially as a little kid, it’s one of the worst things you can think of.
“Now, looking back, it’s probably the best thing that could have happened to me. I wouldn’t have played as many games as I have done.
“Within a year and a half, I was playing for Preston North End and I’ve been playing regular first-team football ever since.
“There’s no thoughts of revenge or anything like that.
“Manchester United are one of the biggest clubs in the world and it’s so hard to get into their team, but I do want to show them how much I have developed since leaving.”
City are flying high in the Championship – a far cry from their battle against relegation last term – and Brownhill believes everyone at the club is singing from the same hymn sheet.
“At the beginning of the season, and in pre-season, we all worked really hard and bought into what the manager believes in,” he said.
“He got everybody reading off the same script and we’ve just taken off from there.
“Everyone starts off at the beginning of the season hoping to be where we are, so that was our aim. We maybe didn’t think we’d be quite as high, but that’s credit to the team and management on and off the pitch.
“Everything’s going really well which gives us massive confidence going into this game. It’s always tough playing Premier League opposition, but that’s where we want to be next year so we’ve got to be competing against these teams.”