Quick answer: competitive cheer developed gradually from the mid-20th century onward, as cheerleading incorporated more athletic skills - jumps, tumbling, and eventually stunts - and organisations began running dedicated competitions judged on technical skill rather than crowd-support performance alone.
From Crowd Support to Technical Skill
For much of its early history, cheerleading's purpose was to support another sport from the sidelines - its quality was judged informally, if at all, by how well it energised a crowd. As jumps, tumbling and eventually partner stunts were added to cheerleading's vocabulary through the mid-20th century, the activity became more technically demanding in its own right.
The Rise of Organised Training
Dedicated training camps and organisations began standardising technique, motions and jumps across schools. Lawrence Herkimer founded the National Cheerleaders Association (NCA) in 1948 and ran its first summer clinic in 1949, and in 1974 Jeff Webb - who had worked for Herkimer - founded the Universal Cheerleaders Association (UCA), which grew into Varsity Spirit. These organisations laid much of the groundwork competitive cheer would later build on.
The First Judged Competitions
From the 1970s, organisations began running national competitions that judged cheer squads directly against each other on technical skill. A collegiate cheerleading championship was broadcast on CBS in 1978, and ESPN began broadcasting UCA's championships in the early 1980s, significantly raising the sport's public visibility.
The Rise of All Star Cheer
A major turning point in competitive cheer's development was the emergence of All Star gyms - private gyms whose teams exist purely to train and compete, with no connection to a school. See History of All Star Cheer for how this reshaped the sport.
Standardisation and Governance
As competitive cheer grew, governing bodies and standardised rules, levels and scoring systems developed to keep competition fair and consistent. In December 2003, US event producers including the NCA and UCA founded the U.S. All Star Federation (USASF) to set common All Star rules, and the first Cheerleading Worlds was held in April 2004. It's a process that continues today, and one this site tracks through its levels and scoring sections.
A Note on Dates
Some early details vary slightly between sources. Where sources disagree, we give the most widely cited version and avoid false precision - the sources we used are listed below.
Sources: Cheerleading (Wikipedia); Varsity Spirit (Wikipedia); UCA Division I-A College National Championship (Wikipedia); U.S. All Star Federation (Wikipedia); The Cheerleading Worlds (Wikipedia)