Charles Girard Tremblay is the co-founder and CEO of Charles Simon, a Montreal-based luxury accessories brand built on the intersection of aeronautical engineering and traditional craftsmanship. He studied engineering in Montreal, where he met his future business partner Simon Maltais. The two competed together in international engineering competitions, including a student formula racing series in which their single-seater design won awards in both the United States and the United Kingdom.

After graduating, Tremblay pursued a career in aerospace and industrial consulting, working for clients including Bombardier, Airbus, and NASA. One of his early assignments took him to Cape Canaveral, Florida, where he taught CAD to engineers whose projects included the lunar rover programme. He later moved to Paris, managing a team of consultants across Europe, an experience that brought him into contact with the luxury goods industry and prompted him to question why engineered products in that space rarely matched the material and technical standards of aerospace or motorsport.

The idea for Charles Simon emerged in 2013. Tremblay founded the company in Quebec in 2014 alongside Simon Maltais, whose background was in communications satellite engineering. The brand launched with a line of luxury carry-on luggage constructed from carbon fibre panels, anodised aluminium, and natural leather. When the pandemic halted international travel in 2020, Charles Simon pivoted to watch accessories, applying the same engineering-led approach to cases, rolls, and storage systems for watch collectors.

Charles Simon products are handmade in the company's Montreal atelier, with production times of three to four months per piece. The brand is distributed through retailers including Mr Porter and Wristcheck, and has built a following among watch collectors drawn to its minimalist aesthetic and uncompromising construction standards. Tremblay has cited Formula One as a reference point for the brand's ethos, describing the sport's week-to-week development culture as a model for continuous improvement.