Needing to outfit his new squad, team founder Curly Lambeau solicited funds from his employer, the Indian Packing Company. He was given $500 for uniforms and equipment in return for the team being named for its sponsor. An early newspaper article referred to the fledglings as "the Indians", but by the time they played their first game "Packers" had taken hold.

Indian Packing was purchased in 1920 by the Acme Packing Company. Acme continued to support the team, which played its first NFL season with "ACME PACKERS" emblazoned on its jerseys.
Why are the Green Bay Packers called the Packers?
The Green Bay Packers are called the Packers because in 1920, the team founder, Curly Lambeau asked his employer, the Indian Packing Company for money to help buy uniforms and equipement.  In return for the funding, the team was named after the sponser.