The car parts and bikes retailer has appointed Loraine Woodhouse, who has been finance director at Waitrose since 2015, as its new chief financial officer.
Ms Woodhouse, who has also held finance director roles at Hobbs, Costa Coffee and Intu, will succeed Mr Mason on November 1.
She also has experience in finance and investor relations at Kingfisher, owner of B&Q and Screwfix.
Halfords chief executive Graham Stapleton said: “I am delighted that Loraine will be joining Halfords as CFO and look forward to working with her.
“She has extensive finance leadership within service-based retail and will be a great addition to the senior team.
“I would also like to take this opportunity to thank Jonny Mason and to wish him every success in the future.”
Ms Woodhouse commented: “I’m really pleased to be joining Halfords and look forward to working with the team to build upon the good foundations in place and to deliver the exciting next phase.”
In May, Halfords warned that profit for the current year would be flat after reporting a 5 per cent fall for 2017-18, saying it would step up investment in the business.
For the year to March 30, Halfords made an underlying pre-tax profit of £71.6m ($96.1m) – in line with analysts’ forecasts but down from £75.4m made in 2016-17.
Halfords said it anticipated the motoring market would remain robust and it continued to see good growth prospects for the cycling market although it did not expect prices to rise in cycling this year as in the previous year.
“Given this, the phasing of our remaining foreign exchange mitigation actions and decisions to accelerate investment in services and customer capabilities, we currently anticipate FY19 (full year 2019) underlying profit before tax to be broadly in line with FY18 (full year 2018),” it said.
Speaking in May, Mr Stapleton, said: “We are pleased with the FY18 performance in a challenging retail environment, with profits in line with expectations. Halfords is a good business with a great future.
“By focusing more on our specialisms and our services, ensuring that we always provide best value to our customers and presenting a more seamless and inspirational omni-channel experience, there is a really exciting future of growth ahead of us. I look forward to presenting our longer-term plans in September.”
Halfords employs around 10,000 staff. The company sells car parts, cycling products, in-car technology, child seats, roof boxes and camping equipment.
Halfords’ cycling own brands in its stores include Apollo, Carrera, Boardman, Pendleton and Wiggins, along with a range of other brands of cycles and accessories.
In motoring, the Halfords Essentials and Halfords Advanced ranges are sold alongside brands such as General Electric, Bosch, Garmin, TomTom, Karcher, Thule and Autoglym.
The company offers more than 70 in-store services including a fitting service called ‘wefit’ for car parts, child seats, satellite navigation and in-car entertainment systems, and a ‘werepair’ service for cycles.
In recent years, Halfords’ performance has been boosted by a line-up of ranges launched by past and present Olympians, including, Sir Bradley Wiggins, Chris Boardman and Victoria Pendleton.