Mr Duddy's role at Home Retail Group, which also owns the Homebase DIY chain, stretches back to 1998 when Argos was acquired by GUS. In his final update to investors as chief executive, he said profits for the year to March 1 will be slightly ahead of market expectations of up to £111 million.
Home Retail also upgraded forecasts in January after Argos enjoyed its best Christmas performance for more than 10 years, driven by progress in its bid to become a digital-led retailer. It has scaled back the print version of the Argos catalogue, alongside plans to close or relocate at least 75 stores over five years.
Mr Duddy, who announced his intention to step down in September, will be replaced by Argos managing director John Walden from today.
Mr Duddy said there were signs that economic conditions are beginning to improve, but the company continues to plan for a subdued environment.
Home Retail said Argos's like-for-like sales increased by 5.2% in the final eight weeks of the financial year, with demand particularly strong in video gaming, televisions, small domestic appliances and white goods.
Like-for-like sales at Homebase increased by 9.3% in the eight-week period, driven by further growth in big-ticket sales such as kitchens and bathrooms.