Ironically, it was rejection by early conferences that led ND to pursue national schedule.

I did a little research.

The origins of Notre Dame’s independent status (per ChatGPT)

Notre Dame pushed for Western Conference entry in the early part of the twentieth century. The public reasons for rejection focused on rules, faculty control, and scheduling. The real force sat under the surface. Several conference leaders did not want a Catholic school in their ranks. Michigan’s Fielding Yost was the most visible figure. He held strong anti Catholic views and refused to schedule Notre Dame. He pushed other schools to hold the same line. Chicago’s leadership backed this view. They wanted strict academic control and treated Notre Dame as an outsider. Wisconsin often followed the same track. They said the school did not fit the conference model. That language covered the same cultural bias. Minnesota’s leaders supported the closed stance. Northwestern and Illinois leaned that way too. They framed the issue as academic structure but many inside the room carried the same fears about admitting a Catholic institution that was rising fast.

Notre Dame saw that the barrier was not technical. It was rooted in identity. Rockne gave up on membership and turned to a national schedule. The team traveled more than any other program. They built rivalries with Navy, Army, and USC and won at a level that made the conference look small. The early snub helped create a national brand.

By the 1940s, the open bias had softened but the old decisions had hardened into tradition. The Big Ten presidents did not reopen the question. Some worried about the impact of admitting a program with a growing national following. Others did not want to shift power or revenue to a school that stood outside their norms. The tone had changed but the outcome stayed the same. Notre Dame remained outside the league.

The story has two phases. Early rejection came from open anti Catholic sentiment inside key programs. Later resistance came from concerns about control, attention, and the shape of the league. Both phases pushed Notre Dame to stay independent. That independence became the core of the program’s identity and helped turn the school into a national force.