Columbo's wardrobe consisted of Peter Falk's own clothes, including the high-topped shoes and shabby suit. Falk bought the famous raincoat, which first appeared in "Fórmula para Matar (1968)," for $15 in 1967, when he got caught in a New York City rainstorm. A life-long cigarette smoker, Falk added the cigar as a personal touch.
The original plan was for a new episode to air every week, which would have meant shooting an episode every five days. As a motion picture star, Peter Falk refused to commit to such a busy schedule. The network arranged for the Columbo segments to air once a month on Wednesday nights.
Peter Falk frequently added in unscripted improvisations such as asking for a pencil, searching for something in his pockets, asking a character to repeat something, rambling about irrelevant trivialities, or adding in a line about Mrs. Columbo. Falk did this to frustrate and annoy his fellow actor (usually the suspect) and generate a genuine "get to the point" moment.
When this show was renewed for a second season, NBC brass wanted Columbo to have a sidekick. Richard Levinson and William Link conferred with Steven Bochco, who was writing the script for the season opener, and together they hatched the idea of giving Lieutenant Columbo a dog as a partner. Peter Falk felt his character had enough gimmicks, between the raincoat, cigar, and Peugeot. When he met the lethargic, drooling basset hound that had been plucked from a pound, Falk knew it was perfect for Columbo's dog.
Columbo's Peugeot convertible can be seen on the "Universal Studios" tour.