“It is not something you think about at the start of your career,” Ford told BBC Sport of his milestone.
“You dream of playing for England, and when you get to do it once it is an unbelievably special moment – to achieve that was the proudest memory of my career.
“Then I suppose you get your head down to work as hard as you can and improve so you might gather a few caps together – that is all I have tried to do really, take each year and campaign as it comes, try to improve, develop and do the right thing for the team.
“I have the opportunity to hit quite a big milestone and it is something I will be very proud of.”
Scrum-half Ben Youngs, who retired from international rugby at the end of the 2023 Rugby World Cup, won 127 caps for his country, the most of any man.
Dan Cole, Jason Leonard, Owen Farrell, Courtney Lawes, Danny Care and co-captain George have also passed the 100-Test mark for England.
Sarah Hunter retired in March 2023 having won 141 caps for England’s women’s team.
“George has been a standout player for over a decade,” said head coach Steve Borthwick.
“Reaching 100 caps is a remarkable achievement, and it speaks volumes about both the professional and the person he is.
“Everyone in the squad is incredibly proud to share this moment with him.”
Borthwick has said that Argentina will be favourites across the two-Test series after the Pumas’ victory over the British and Irish Lions in Dublin last month continued their fine run of form.
Argentina are ranked fifth in the world, one place above England.
The second meeting between the two teams takes place in San Juan on 12 July.
England: Steward; Roebuck, Slade, S Atkinson, Muir; Ford, Spencer; Baxter, George, Heyes, Ewels, Coles, B Curry, Underhill, Willis.
Replacements: Dan, Rodd, Opoku-Fordjour, Cunningham-South, Pepper, Dombrandt, Van Poortvliet, Murley