Korey Smith played for the Norwich City Under 16s during the 2006/7 season. He became a first year scholar in the summer of 2007. A central-midfielder from Hatfield, Korey was previously with Arsenal. He is of Jamaican descent.

Korey was awarded his first professional contract with Norwich in May 2008

After being called up to the bench a couple of times, Korey was handed his debut as a substitute in the 1-0 defeat to Sheffield Wednesday at Carrow Road on 4th April 2009.

Korey scored his first goal for Norwich in the 5-2 win over Wycombe on 22nd August 2009. Korey was one of the success stories of the 2009/10 season making 40 appearances and scorimg 4 goals as City won the League One title.

He made 32 appearances in 2010/11 as Norwich won promotion to the Premier League

Korey's ankle was injured in the September 2011 FA Premier Reserve Team clash at Newcastle and was out of action until January 2012. Returning from injury, he was loaned in lat January 2012 to Barnsley to get match fitness. He made his debut on 31st January 2012 and was named Man of the Match for his two assists in the 3-2 win over Derby. This was extended in March 2012 until the end of the season.

Korey signed a one year extension to his contract in July 2012

On 15th September 2012, Korey joined Yeovil on a three month loan and came off the bench to make his debut in the 1-0 defeat by MK Dons that day.

Korey made 19 appearances for Yeovil (17 league appearances and two in the JP Trophy)

Korey joined Oldham on a month's loan on 15th March 2013. He made 10 appearances for Oldham

On 20th May 2013, Norwich announced that they would not be renewing Korey's contract when it expired at the end of June 2013. He had made 73 appearances for Norwich. Korey signed a two year contract with Oldham Athletic on 20th June 2013. He said “At the end of the day I have returned because I enjoyed living here and also enjoyed my football. I enjoyed my time here and the lads, manager and everybody around the club were quality. The manager was, like me, a small midfield player and he has helped me and given me advice to improve my game. As he played in my position, he gives me freedom to express myself. I decided this was the best place to come. Hopefully I will play regularly and my career can kick on. It is the start of a new adventure and I am looking forward to the challenge. I’d been at Norwich for a long time and it will be exciting to play somewhere else.”

Korey moved to Bristol City on 27th June 2014 for an undisclosed fee. He signed a three year contract with the Robins. He had made 52 appearances for Oldham in 2013/14 scoring twice.

In his first season with Bristol City, they won the Johnstone's Paint Trophy and the League One title, securing promotion on 14th April 2015 witha 6-0 win over Bradford.

After six seasons and 196 appearances, Smith left Bristol City on 9th August 2020 when his contract expired. He said "Bristol City have told me they are not able to offer me a new contract at this time. So me and my family will now be looking for a new opportunity." That opportunity arose on 14th August 2020 when he signed a two year contract with Swansea City despite interest from Notts Forest and Cardiff City. Smith said "From the moment the club knew I was available the manager [Steve Cooper] was on the phone to me, he showed me the project and was really keen to get me through the door. He told me all about the place, the fans and the stadium. I am really excited to get going. The club showed how much they wanted me, there was no messing around."

Korey was one of three players who left Swansea at the end of May 2022 on the expiration of their contracts (the others being Ben Hamer and Yan Dhanda). Smith had played 77 games for the Swans.

On 16th July 2022 he became League One side Derby County's 11th signing of the summer, signing a two year deal.

Smith was in the Derby side that beat Carlisle 2-0 on 27th April 2024 to secure promotion to the Championship. He played in the centre of midfield alongside Ebou Adams. On 18th May 2024 Derby announced that Korey would be leaving on the expiry of his contract. He had played 85 games for Derby, scoring once.

On 17th July 2024 he signed a two year contract with Cambridge United.