Chuck Noll was an assistant coach for the San Diego Chargers and the Baltimore Colts before becoming the Pittsburgh Steelers head coach. He was the defensive coordinator of the Baltimore Colts (under head coach Don Shula) during their 13–1 season in 1968, in which the team set an NFL record of fewest points allowed (144). The 1968 Colts won the NFL championship by stomping the Cleveland Browns 34–0 in Cleveland, but the heavily favored Colts were shocked by the upstart AFL champion New York Jets, 16–7, in Super Bowl III at the Orange Bowl in Miami.

Noll was named the 14th head coach of the Pittsburgh Steelers on January 27, 1969, after Penn State coach Joe Paterno turned down an offer for the position. Noll implemented a defensive system in Pittsburgh that became the legendary "Steel Curtain" defense. His coaching style earned him the nickname of Chaz The Emperor by sports announcer Myron Cope. Noll is the only head coach to win four Super Bowls, coaching the Steelers to victory in Super Bowl IX (1975), Super Bowl X (1976), Super Bowl XIII (1979), and Super Bowl XIV (1980).

The key to Noll's coaching success during this unprecedented run was the Steelers' skill in selecting outstanding players in the NFL college player draft. Noll's first round one pick was Joe Greene, a defensive tackle from North Texas State, who went on to become a perennial All-Pro and anchor the defensive line. During the next few years, the Steelers drafted quarterback Terry Bradshaw (Louisiana Tech) and running back Franco Harris (Penn State) as round one picks. In the 1974 draft, Noll and the Steelers achieved a level of drafting success never seen before or since, when they selected four future Hall of Fame players with their first five picks: wide receivers Lynn Swann and John Stallworth, middle linebacker Jack Lambert, and center Mike Webster. To this day, no other draft by any team has included more than two future Hall of Famers, including the Steelers themselves in 1970. (Quarterback Terry Bradshaw and cornerback Mel Blount.)

A very meticulous coach, Noll was well-known to coach players on basic fundamentals in practice, such as the three-point stance, that players were already expected to know. For instance, Andy Russell, already a Pro Bowl linebacker before Noll arrived and one of the few players Noll kept after purging the roster his first year, was told by Noll that he didn't have his feet positioned right. Russell went on to become a key member for the first two Super Bowl teams and started the linebacker tradition that continues today in Pittsburgh as a result of Noll's attention to detail.

While most of his contemporaries (as well as current NFL head coaches) enforced strict curfew rules on its players, Noll was very lax on off-the-field behavior. This was shown at Super Bowl IX. While Noll's counterpart--Minnesota Vikings head coach Bud Grant--strictly kept his team in their hotel rooms except for practice before the game, Noll told his team upon arriving in New Orleans to go out on Bourbon Street "and get the partying out of your system now." It can be argued that Noll allowing his players to go out while in New Orleans helped them be more relaxed when they played the Vikings and won 16-6.

The hallmark of the team during the 1970s was a stifling defense known as the Steel Curtain, loaded with All-Pros. The starting 11 (linemen L. C. Greenwood, Joe Greene, Ernie Holmes (later Steve Furness), Dwight White, linebackers Jack Ham, Jack Lambert, Andy Russell (later Loren Toews), defensive backs Mel Blount, J.T. Thomas, and safeties Glen Edwards (later Donnie Shell) and Mike Wagner had a collective level of talent unseen before in the NFL.

The teams that won Super Bowls IX and X used a run-oriented offense, primarily featuring Franco Harris and blocking back Rocky Bleier. Over the next few years, Terry Bradshaw matured into an outstanding passer, and the teams that won Super Bowls XIII and XIV fully utilized the receiving tandem of Lynn Swann and John Stallworth.

Noll was never a coach who sought a lot of media attention, and his 1970s teams were so talented that his contributions as head coach (and architect of the team) often were overlooked.

In 1989, Noll finally achieved some recognition as NFL Coach of the Year, when he guided the Steelers into the second round of the playoffs. The team was not especially talented, and lost its first two regular season games by scores of 51–0 and 41–10. However, Noll did a remarkable job in keeping the team focused and steadily improving its play, as they made the playoffs and played competitively in two playoff games.

Chuck Noll retired as Steelers head coach in 1991 with a record of 209–156–1. He was elected to the Pro Football Hall of Fame in 1993.

Noll still has a residence in suburban Pittsburgh. However, he spends most of his time at his home in Florida. His mobility has been limited by chronic back problems. Noll holds the ceremonial title of Administration Adviser in the Pittsburgh Steelers' front office, but has had no real role in the team's operations since his retirement. He spends about half the year in Pittsburgh, with his devoted wife Marianne. They have a son named Chris who is a teacher in a private high school in Connecticut.