Coach Robert "Red" Miller

Red Miller, who turned the hapless Denver Broncos into a defensive powerhouse and guided the team to its first Super Bowl, in 1978, in his first season as a head coach, died on Wednesday in Denver. He was 89.

His wife, Nan Miller, said the death, at a hospital, was caused by complications of a stroke he had on Sept. 11 at his home in Denver while watching a televised “Monday Night Football” game between the Broncos and the Los Angeles Chargers.

When Miller took over as head coach for John Ralston in 1977, the Broncos had been perennial National Football League also-rans. The team had only three seasons with winning records and had never made it to the playoffs since its first season, in 1960.

Players on the Broncos had soured on Ralston, who they thought was aloof and ineffectual; a dozen players issued a statement after the 1976 season expressing their lack of confidence in him.

Miller’s approach to coaching was decidedly more hands-on. He was bloodied during practice while demonstrating a blocking technique to Claudie Minor, a 280-pound offensive tackle, without wearing a helmet. He joined the rookies Steve Schindler and Rob Lytle in a training-camp rookie “talent show,” in which he banged out ragtime on a piano.

Miller did not inherit a mess from Ralston. The Broncos were coming off their best season to date, with a 9-5 record, and many of the pieces for their first playoff run were already in place, including the core of the 3-4 defense that became known as the Orange Crush.

Anchored by All-Pro players like the linebackers Randy Gradishar and Tom Jackson, the defensive backs Bill Thompson and Louis Wright, and the lineman Lyle Alzado, the Orange Crush became one of the most feared defenses in the N.F.L. under Miller’s leadership.

The biggest addition to the roster that year was the veteran quarterback Craig Morton, whom the Broncos had acquired from the Giants in a trade.

After beating the Pittsburgh Steelers, 34-21, and the Oakland Raiders, 20-17, in the playoffs, the Broncos faced Tom Landry’s Dallas Cowboys in Super Bowl XII at the Superdome in New Orleans. Denver’s offense crumbled in the face of Dallas’s so-called Doomsday Defense, turning the ball over eight times in the course of the game, seven in the first half alone.

In the third quarter Miller replaced Morton, who had thrown four interceptions, with his backup, Norris Weese, and Denver’s defense held the Cowboys to just 13 points in the first half despite all the turnovers. But Dallas prevailed, winning 27-10.

Miller led the team for three more seasons and to two more playoff appearances, accumulating a 40-22 regular season record. But he was fired in 1981, after an 8-8 season, when Edgar F. Kaiser Jr. bought the team and replaced him with Dan Reeves, the Cowboys’ offensive coordinator.

“The city seems a little stunned,” the Broncos’ public relations coordinator, George McFadden, told The New York Times that year. “Red Miller was awfully popular.”

Since that first appearance in the Super Bowl, the Broncos have returned to it seven more times, winning three titles.

Robert Neil Miller was born in Macomb, Ill., on Oct. 31, 1927, to John Miller, a coal miner, and his wife, Jennie, a homemaker. One of 10 children, Miller, nicknamed for his red hair, grew up poor and was the only one of his siblings to graduate from college.

He played offensive guard at Western Illinois University in Macomb and received a bachelor’s degree before starting his coaching career at the high school level.

He returned to Western Illinois as an assistant coach under Lou Saban, earning a master’s degree while there, then joined Saban after he became coach of the Boston Patriots (now the New England Patriots) in 1960. Miller, who specialized in offense, was also an assistant coach with the Buffalo Bills, the St. Louis Cardinals and the Baltimore Colts before he became Denver’s head coach.

After he left the Broncos, he was briefly the head coach of the Denver Gold of the short-lived United States Football League, then worked as a stock broker. He married Nancy Gilbert in 1990.

In addition to his wife, he is survived by a son, Steve, from an earlier marriage, which ended in divorce; a stepson, Jeff Vasilion; and five grandchildren. His daughter, Lana Ritzel, died in 2011.