A club-developed player is defined as one who has been registered to the club for at least a year before the end of his under-19 season.
The new rules were agreed following a meeting of all 72 EFL clubs.
"I am confident that this decision will have a positive and lasting impact," said EFL chief executive Shaun Harvey.
"It is imperative that we provide young players not only with a platform, but also with the belief that opportunities will be made available to progress from youth to senior football."
Teams have previously had to include six home-grown players, defined as those registered with a club in England or Wales for three seasons, or 36 months, before their 21st birthday.
English Football League clubs will have to name at least one "club-developed" player in their matchday squads from the start of the 2018-19 season.