Mildred June was born on December 23, 1905, in St Louis, Missouri. When she was a child her family moved to Kansas and eventually settled in California. She attended Hollywood high school and took dancing lessons. At the age of fifteen Mildred was discovered by producer Mack Sennett. She became one his bathing beauties and worked as an extra in his films. Mildred appeared in dozens of short films including Dog Shy with Charley Chase and Hook and Ladder with Hoot Gibson. She also starred in a series of two reel comedies with Billy Bevan. Although she enjoyed making comedies she dreamed of becoming a dramatic actress. Mildred married Herbert Edward Capps, a twenty-five year old dentist, in 1922. The following year she was given the lead in the drama The Greatest Menace.

She was signed by Universal studios but her career never took off. Mildred returned to Mack Sennett's studio and appeared in the 1927 comedy Crazy To Act. She divorced her husband and had a brief romance with with real estate executive Jimmy Houston. Unfortunately by 1928 she was unemployed and battling a serious alcohol problem. Mildred married her second husband, Bud Sheehan, in 1930. Sadly he passed away a few years later. In 1936 she had a bit part in the Laurel and Hardy film Our Relations. It would her last acting role. On June 19, 1940 Mildred passed away from cirrhosis of the liver caused by her alcoholism. She was only thirty-four years old. Mildred was cremated and her ashes were buried at Hollywood Forever cemetery in Hollywood, California.