Arlo was born on November 5, 1931 in Antelope, Montana to parents Hjalmer and Sophia Petersen. After school he joined the United States Navy in March of 1950 and proudly served on the Franklin and Munro Ships with time spent in combat during the Korean War. After honorably discharged from the Navy in 1954, Arlo spent the remainder of his working career in a variety fields. Some of the companies he was most proud of having been employed with are the Smelter Plant, Carpenter Paper, Haggerty, and Heritage Inn.
A few years after his service in the Navy, Arlo met who would be the love of his life, Andrea Pauline who he later married in Great Falls during the year of 1959. From this union they were blessed with 1 daughter and 3 sons.
Arlo was preceded in death by his loving wife Andrea Petersen in May of 2008 as well as both parents.
He is survived by his daughter, Deborah (Jim) Montgomery; sons, Kurt Petersen, Robert (Sharon) Petersen, Terry (Juliet) Petersen; sister, Lois Pritchard; 6 grandchildren and 2 great-grandchildren.