Mr Garioch started working at the Caledonian aged 15, in 1963. He was born in Easter Road and attended Liberton School until joining the hotel staff, but his career nearly took a very different path.
"I was good at metalwork at school," he said. "The headteacher said I should try for an apprenticeship at Ferranti's, making airplane parts. I went for an interview and was offered a five-year apprenticeship at 4.50 a week, and I thought to myself, 'I'm not going to go far in the world with that!'
"I saw an advert in the paper for a page boy's position. I didn't even know what it was," Mr Garioch added.
"Back then it was like being in the army. The head concierge would look you up and down and say 'Cut your hair, boy; cut your nails.'"
He also worked for several years as a cocktail barman and wine waiter, before becoming a porter and later a concierge.
Mrs Garioch, also from Edinburgh, has worked as a room assistant in the housekeeping department for ten years.
"I just fancied it," she says, but says her family connections also led her to the Caledonian after working as a private housekeeper. Mrs Garioch's mother was on the hotel staff for 15 years, and her father's mother, Mary Taylor, worked in the staff canteen for 20 years. "It was Helen's granny who introduced us," Mr Garioch said.
The pair both credit the friendliness of fellow staff members for the length of their time working at the Caledonian, particularly Mr Garioch. "In other departments people come and go, but there must be 150 years' experience in my department.
"We're all Scottish; it's the best team. That's part of the reason why people keep coming back. There's regular guests I know who have been coming back for 30 years.
"The dcor might change, but the hotel will stay the way it is," Mr Garioch said.
The pair have marked not just a professional milestone, but a personal one: the couple, who have two children, celebrated their 40th wedding anniversary on November 11.
When not working at the hotel they enjoy gardening, karaoke, and looking after their three grandchildren.
"We used to go out every Saturday to the Endsleigh Bar on Queensferry Street, where our daughter was the DJ," says Mr Garioch.
In total, 22 members of staff were recognised for reaching landmarks of anywhere from three years to 20, as in the case of Duncan Pattie, 46, who began working at the Caledonian in 1990. At a special award luncheon on Friday 26 November, general manager Willy Blattner recognised each member of staff with a certificate and gift voucher.