Janet was born November 25th, 1936, in Pondera County Montana. She was raised in Cut Bank, Montana.  In 1953, she won the state high school championship title of Rodeo Queen. Janet was the first state Rodeo Queen in Montana's history. She had a love of horses, a passion for rodeos, and was a member of the Daughters of American Revolution (DAR).

In 1956, she met and married U.S. Air Force member Robert "Bob" Murphy. Together they had three sons Mike, Jim, and Tom Murphy. Janet also attended college at Montana State University in Bozeman. In 1968, she fell in love and married Russell Mann. They moved to Elgin, Oregon and started "Mann's Racing Quarter Horses".

Janet and Russ were both members of the Eastern Oregon Quarter Horse Association. She was active in the local 4-H and boy scouts troops. In 1973 they moved to Vaughn, Montana for their love of ranching and farming. Janet worked at the Phillips '66 Refinery in Great Falls from 1977-1979. She was active with the Montana Quarter Horse Association as well as racing quarter horses. Janet moved to Shelby in 1987 and became a dispatcher for the Toole County Sheriff's office. She was with the office for 15 years before retiring in 2004.

Six years into her retirement, her husband Russell sadly passed away. Janet moved to Fort Benton, Montana in 2013 to be closer with family where she made new friends and spent time along the Missouri River. She lived near her son, Jason Mann, and her special friend Royce Cappis. Janet lived in a cute yellow house with her dog named Ricky. Her favorite hobbies in town were spending quality time with her family and friends as well as spending time up at Jason's cabin. Janet also looked forward to her trips up to Glacier National Park with her granddaughters in the summertime. She loved her family and enjoyed every moment with them.

On January 21, 2025, Janet passed away at age 88 in Fort Benton, Montana.

She was preceded in death by her son Mike Murphy and her husband Russell Mann. Janet's surviving family members include her sister Nora, her three sons, her six grandchildren, and her eight nieces and nephews. Janet will be dearly missed by all of her family and friends.

There will be a celebration of life for Janet on Friday, July 11th at the Palace Bar in Fort Benton from 2-4 p.m. This celebration is open to everyone that cared for Janet. Snacks and beverages will be provided.