There he goes, into that drugstore. He's stepping on the scales. Weight? 237 pounds. Fortune? Danger. Whoooooo is it? The Fat Maaaan!

J. Scott Smart was a natural for the part of Brad Runyon. He would often say, "It takes a fat man to sound like a fat man." Brad Runyon weighed-in at 237
pounds (or 239/241 pounds, depending on which episode), Jack Smart tipped the scales at around 270 pounds, only being 5- foot, 9-inch tall. Jack Smart
was not only a famous radio actor, also an accomplished stage actor, jazz historian and musician, amateur gourmet chef, newspaper writer, and artist.
There was a steady climb in popularity that caught the attention of Norwich Pharmaceutical Company. They wanted a way to advertise their Pepto Bismol.  
Norwich Pharmaceutical Company sponsorship of "The Fat Man" started around February 1947. The series lasted six seasons.
In 1950 Dashiell Hammett was called before the House Un- American Activities Committee and he refused to give names. He was tried and imprisoned
for his failure to cooperate with the Committee and was blacklisted along with the many other fine artists and entertainers who fell victim to the anti-
communist hysteria of the day.
Norwich Pharmaceutical Company was quick to withdraw its sponsorship.
In 1951, there was a film titled The Fat Man starring J. Scott Smart, along with Jayne Meadows, Rock Hudson; John Russell and circus clown Emmett
Kelly, wherein the investigation of a dentist's murder leads Runyon to a circus showdown.
Universal-International removed his name from the titles of The Fat Man movie. It was only released because it was already made by the time of Dashiell
Hammett's situation.

No one is sure how much Dashiell Hammett helped develop the series, or if he just lent his name. In the Martha's Vineyard Gazette of September 6, 1949
he was quoted as saying, "My sole duty in regard to these programs is to look in the mail for a check once a week. I don't even listen to them. If I did, I'd
complain about how they were being handled, and then I'd fall into the trap of being asked to come down and help. I don't want to have anything to do
with the radio. It's a dizzy world--makes the movies seem highly intellectual."

There was also an version made in Australia, syndicated on the Artansa lable, about 1954.  There are at least 36 shows available from vendors.  The
Australian Fat Man was played possibly by Lloyd Berrell.  Although not featuring J. Scott Smart, who really fit the part, the series is quite good.
The Fat Man (1951) movie with sleuth J. Scott
Smart and John Russell promotional photo.
The Fat Man
List Of Shows
The Fat Man 46-01-21 (001) The 19th Pearl
The Fat Man 46-02-11 (004) The Twice Told Secret
The Fat Man 46-07-08 (025) The Black Angel
The Fat Man 46-09-09 (034) The Crooked Horse
The Fat Man 47-XX-XX (000) Murder Plays Hide and Seek
The Fat Man 47-10-03 (090) A Window For Murder
The Fat Man 48-04-09 (117) Murder Rents A Flat
The Fat Man 49-04-01 (168) Murder Wins The Draw
The Fat Man 49-07-22 (184) Murder is the Medium
The Fat Man 51-01-17 (253) The Nightmare Murder
The Fat Man 51-09-05 (286) Order For Murder
The Fat Man shows done in America
The Fat Man shows done in Australia
The Fat Man XX-XX-XX (01) Murder Squares The Triangle
The Fat Man XX-XX-XX (02) Murder Plays The Horses
The Fat Man 45-12-01 (03) Murder Sends A Christmas Card
The Fat Man XX-XX-XX (04) Murder Runs A Want Ad
The Fat Man XX-XX-XX (05) Murder Wears A False Face
The Fat Man XX-XX-XX (06) Murder Stalks The Dead
The Fat Man XX-XX-XX (11) Murder Through A Crystal
The Fat Man XX-XX-XX (12) Murder Makes A Ham
The Fat Man XX-XX-XX (15) Murder and The Peacock
The Fat Man XX-XX-XX (16) Murder and The Undertaker
The Fat Man XX-XX-XX (17) Murder Seeks a Lost Penny
The Fat Man XX-XX-XX (18) Murder Makes a Statue
The Fat Man XX-XX-XX (21) Murder Rings A Bell
The Fat Man XX-XX-XX (22) Murder Repeats Itself
The Fat Man XX-XX-XX (23) Murder Rides A Wheelchair
The Fat Man XX-XX-XX (24) Murder Finds A Coffin
The Fat Man XX-XX-XX (25) Murder For Sale
The Fat Man XX-XX-XX (26) Murder By Mail
The Fat Man XX-XX-XX (29) Murder Shows An Unfamiliar Face
The Fat Man XX-XX-XX (30) Murder Makes a Kings Coffin
The Fat Man XX-XX-XX (33) Murder Makes a Black Moon
The Fat Man XX-XX-XX (34) Murder Shows A Phantom Face
The Fat Man XX-XX-XX (35) Murder Makes a Silent Partner
The Fat Man XX-XX-XX (36) Murder Makes Music
The Fat Man XX-XX-XX (37) Murder Writes A Story
The Fat Man XX-XX-XX (38) Murder Meets an Uncertain Lady
The Fat Man XX-XX-XX (39) Murder Shows A Card
The Fat Man XX-XX-XX (40) Murder Makes a Pay Off
The Fat Man XX-XX-XX (45) Murder In The Dark
The Fat Man XX-XX-XX (46) Murder Shows Eyes In The Dark
The Fat Man XX-XX-XX (47) Murder Makes a Broken Heart
The Fat Man XX-XX-XX (48) Murder Pays Dividends
The Fat Man XX-XX-XX (49) Murder Appears Out Of The Past
The Fat Man XX-XX-XX (50) Murder Made Stylish
The Fat Man XX-XX-XX (51) Murder Takes A Picture
The Fat Man XX-XX-XX (52) Murder is Forecast