Juneau was the grandnephew of Solomon Juneau (1793–1856), a fur trader, land speculator, and politician who helped found the city of Milwaukee, Wisconsin. Juneau played football at Wisconsin as an end and halfback from 1899 to 1902 and captained the Wisconsin Badgers football team in 1902. He began his coaching career in 1903 at Fort Atkinson High School in Fort Atkinson, Wisconsin. Juneau retired from coaching 1923 and entered the real estate business. He died on October 9, 1949 at the age of 70.