There was a real "Ice Cream War" in Glasgow in 1984, and it led to murders within the city. It was really a drug-land turf war by gangs who used ice cream vans as a front. Writers Douglas Skelton and Lisa Brownlie cover the story in their 1992 book "Frightener". The deaths of van-driver Andrew Boyle (who had resisted being involved in drug dealing) and his family happened in April 1984, four months before "Comfort and Joy" was released, and as star Bill Paterson acknowledges, this had an impact on the film's reception: "It wasn't a great time to launch a light-hearted look at the ice-cream business in Glasgow."
Peter Capaldi's family, who were quite well known for being ice cream makers, supplied all the ice cream for the film. (Capaldi worked with Forsyth on Local Hero (1983)).
Mark Knopfler, lead singer of Dire Straits, wrote the soundtrack for this film. Lyrics from a previous Dire Straits album "Love Over Gold" are used as dialogue in the film: one of Alan Bird's radio colleagues says, "I hear the seven deadly sins and the terrible twins came to call on you"; Alan mutters "Dire straits"; his colleague replies "the bigger they are, babe, the harder they fall on you". "I hear the seven deadly sins came to call on you", and "The bigger they are, baby, the harder they fall on you" are both lyrics from the song "It Never Rains".
George Rossi, who makes his acting début here alongside his brother Peter Rossi is a member of a well-known ice cream family, and he himself worked on the vans growing up.
The photo on Hillary's (Rikki Fulton) desk of a young man in naval uniform actually is the young Fulton, who served in the Royal Navy 1941-45.