Walter Breuning plans to attend an invitation-only birthday party on Tuesday afternoon at the Rainbow Retirement Community in downtown Great Falls.
He is expected to have cake and deliver a speech at the party that will include Montana Gov. Brian Schweitzer and representatives from Guinness World Records.
Breuning was born on Sept. 21, 1896, in Melrose, Minn., and moved to Montana in 1918. He worked for the Great Northern Railway for 50 years.
According to CBS Affiliate KRTV, Breuning takes one aspirin each day, eats two meals a day, and strolls the halls of the Rainbow Retirement Center every morning, always wearing a suit and tie.
His mind is extremely sharp, remembering his grandfather talking about fighting in the Civil War when Walter was just three years old. He can recall where he was when President McKinley was assassinated.
"If you're in good health, you've got everything there is," he told the Great Falls Tribune.
His family was less fortunate: Breuning's father, a civil engineer, died at 50, and his mother, a housewife, at 46. Two brothers and two sisters died in their 70s, he said.
His wife, Agnes, died in 1957. The couple had no children.
Breuning's advice for living to a ripe old age? Stay active in body and mind, don't eat too much and be good to people.
"Keep your mind busy and your body busy at all times," he said. "You'll find out. I got told years ago … keep your mind going or it just goes right down the chute."
Last year Breuning told CBS News' Steve Hartman, "You come back in 4 or 5 years and I think I'll be here." He even promised Hartman an exclusive interview.