Sonny Carey was named as part of Norwich's Under 10s squad in 2010/11 and the Under-13s in 2013/14. He played for theUnder-14s in a tournament in Woudenberg. near Utrecht in June 2014. He was listed by Soccerway website as being on the fringes of the Under-18 sqaud in 2016-17

After departing Norwich, he trialled with Cambridge and Oxfor as well as playing for the English Colleges FA national team in 2018/19. He has also been part of Norwich's Community Sports Foundation (CSF) shadow squad, who are coached by Linnets midfielder Ryan Jarvis. He also played for Wroxham.

On 1st June 2019, he signed for Kings Lynn Town. Linnets director of football Robbie Back added: "Sonny is a player who we have been keeping tabs on for the last year. He is an exciting talent and has a great future ahead of him. We are delighted to bring him to the football club."

On 17th June 2020 it was confirmed that Lynn were winners of the National League South, on a points per game basis due to the premature ending of the season because of Covid-19, and would be promoted into the National League.

At the end of April 2021 it was reported that Bolton Wanderers have an interest in signing Carey in the summer of 2021. The same article reported that Championship sides Bournemouth and Swansea were also admirers of the midfielder whose reputation had been rising during the 2020/21 campaign. Carey said: “I just let all the noise in the background look after itself and I just focus on when I get on the pitch doing what the gaffer has told me to do and give 100pc for the team. It’s good hearing the stuff but at the end of the day it is all talk and interest and that’s it until the end of the season and we will see what happens.”

On 25th June 2021 Carey signed a three year deal with Blackpool for an undisclosed fee believed to be six figures.

Carey was on the bench when Blackpool lost 3-2 at home to Millwall on 28th April 2023 resulting in their relegation from the Championship.