Tom McCloskey, a wealthy Philadelphia businessman was interested in owning a professional sports team.

While attending the 1973 Super Bowl, Lamar Hunt broached the subject of McCloskey starting a North American Soccer League (NASL) franchise in Philly.

In the semifinals, the Atoms crushed the Toronto Metros 3–0, then easily handled the Dallas Tornado 2–0, to take the 1973 NASL title.

(Miller was named NASL Coach of the Year, the only US-born manager to win that award in the league's 17-year history.)

In 1974, McCloskey promoted Miller to general manager, a position he held in addition to his coaching duties.

In 1975, he drafted Chris Bahr who became the 1975 NASL Rookie of the Year and later became a standout National Football League placekicker.

After Dallas lost that semifinal match with the New York Cosmos, Miller announced his resignation as coach in the locker room.

[1] In doing so he joined Eddie Firmani and Ron Newman as the only coaches to win NASL titles in both the outdoor league and the indoor variant.

[1] When Dettmar Cramer, the first-ever full-time head coach of the U.S. national team, quit in 1975, he was replaced by Miller on an interim basis.

Miller's tenure was brief, only two matches: in a home-and-home series of friendlies against Poland, the U.S. was crushed 7–0 in Poznań and 4–0 in Seattle.

Instead he entered team management with the Cleveland Force of Major Indoor Soccer League (MISL).

In July 1992, the MISL folded and the Crunch moved to the National Professional Soccer League (NPSL).

In 2008, Miller was inducted into the New Paltz Hall of Fame along with the 1965 Men's championship soccer team.