Declan began Karting in 2005. He moved into cadet karts and won 4 out of 5 novice cups available.
In 2007 Declan became Mini Max Hooton Park Champion and took multiple wins at local club rounds.
In 2008 Declan moved into Junior Max, becoming MBKC winter series champion at 3 sisters, Dragon Master winner at Gyg in Wales and gained 3rd in the Rotax Cup at 3 Sisters. Declan finished 2nd over all in the MBKC Championship.
In 2009 Declan joined Junior Max. He finished 14th in Formula Kart Stars. That same season, Declan finished 2nd in the Dragon Master Cup. He also gained multiple club wins around the country.
In 2010 Declan continued in Junior Max and became MBKC winter series winner at 3 Sisters and 2nd overall in the championship as well as Dragon Master Cup winner at Gyg. Declan also gained multiple wins around the UK. He finished 15th in the Super One Championship and joint 3rd in the Formula Kart Stars Championship. That season Declan also became Cumbria O Plate winner and won the last round of Formula Kart Stars at Ellough Park. The 2010 season also gave Declan a taste of the future in the form of the Ginetta junior scholarship, with getting through to the last 12.
2011 saw the eventual move from Karting. Joining the Ginetta Juniors and gaining multiple top 10 finishes. Ending a successful year in a very respectable 13th position in the championship.
In 2012 the ever confident Declan began racing in the VdeV Endurance Championship. The Dijon 2hr race saw a victory in his class, 3rd in Prototypes and 6th overall. 2012 also witnessed Declan enter the Ginetta GT Supercup, the support race to the British Touring Car Championship. First time out at Oulton Park Declan put his car on pole by just over 7 tenths of a second and finished 3rd on the Sunday race. At knockhill Declan finished 2nd and 3rd. At Rockingham Declan finished a 3rd and at Silverstone gained 2nd and 1st. The last round at Brands Hatch saw Declan gain 1st and 2nd and 3rd. 2012 Proved to be a very successful year, capping off what is already a remarkable career so far.
In 2013, Declan signed for Century Motorsport to compete in the British GT Championship. Partnering Zoë Wenham for the first 5 rounds and Nathan Freke for rounds 6 and 7, in a GT4-class Ginetta G50. He finished 1st in the first two rounds at Oulton Park and became one of the youngest ever winners in the series.