Similar names for the average American include Joe Citizen/John Citizen/Jane Citizen, Joe Sixpack/Jane Sixpack, Joe Taxpayer/John Taxpayer/Jane Taxpayer, Joe Voter/John Voter/Jane Voter, Mr. and Mrs. America and Sally Soccer-mom.
Wikipedia: John Q. Public
John Q. Public (and several similar names; see the Variations section below) is a generic name in the United States to denote a hypothetical member of society deemed a "common man." He is presumed to represent the randomly selected "man on the street."
Similar terms include John Q. Citizen and John Q. Taxpayer, or Jane Q. Public, Jane Q. Citizen, and Jane Q. Taxpayer for a woman. The name John Doe is used in a similar manner. For multiple people, Tom, Dick and Harry is often used.
Roughly equivalent, but more pejorative, are the names Joe Six-pack, Joe Blow, and Joe Shmoe, the last of which implies a lower-class citizen (from the Yiddish schmo: simpleton, or possibly Hebrew sh'mo: (what's)-his-name).
The term "John Q. Public" was the name of a character created by Vaughn Shoemaker, an editorial cartoonist for the Chicago Daily News, in 1922. Jim Lange, the editorial cartoonist for The Oklahoman for 58 years, was closely identified with a version of the John Q. Public character, whom he sometimes also called "Mr. Voter". Lange's version of the character was described as "bespectacled, mustachioed, fedora-wearing". In 2006 the Oklahoma State Senate voted to make this character the "state's official editorial cartoon."
27 July 1920, Salt Lake Telegram (Salt Lake City, UT), "Penny Demand Crowding Supply," pg. 15:
WASHINGTON, July 27. -- Treasury officers and particularly the director of the mint, are wondering where all the pennies go. John Public can't buy anything with a penny any more, not even at a bargain rush, yet the mint cannot keep up with the demand.
10 August 1922, New York (NY) Evening Mail, pg. 12:
John Q. Public Tells Views On The Giants.
6 November 1926, Sheboygan (WI) Press, pg. 2, col. 1:
Chicago - The American hog and his companions, the sheep and the sheer, have become drug stores in addition to their regular duties of supplying hams, steaks and chops to hungry John Q. Public.
21 July 1927, Los Angeles Times, pg. 2:
NEW YORK, July 20. (Exclusive) - Gloria Swanson's swan song as a Long Islander was sung as the raucous bark of the auctioneer yesterday. But Mr. and Mrs. John Q. Public, whatever they think of Gloria on the screen, didn't enthuse over buying her cast-off eastern furniture.
8 February 1938, Brownsville (TX) Herald, 'Jimmie Fidler In Hollywood," pg. 2, col. 3:
They remind me of the boy who cried "wolf" -- and unless they tone down their advertising John and Jane Public are very apt to follow the example of the herders who refused to be fooled by the boy's cries for help.
v. 43 - 1938
There is a shower of prizes, of course, silver cups, medals, placques and trophies for the masters who set us the pace, and because of the increasing interest in such things John and Jane Q. Public have been flocking to this greatest show on earth in increasing numbers.
7 March 1940, Christian Science Monitor, "Chicago Woman's City Club Aids Better Housing Drive," pg. 5:
Jane Q. Public. wife of the well known John Q., has decided that she is going to do something to improve housing in Chicago.
New York (NY) Times
Vaughn Shoemaker; Created John Q. Public
Published: August 22, 1991
Vaughn Shoemaker, an editorial cartoonist who created the character John Q. Public and won two Pulitzer Prizes, died Sunday at the Windsor Park Manor Medical Center in Carol Stream, Ill. He was 89 years old and lived in Carol Stream, a Chicago suburb.
He died of cancer, said his physician, Dr. Maurice Birt.
Mr. Shoemaker's most familiar character, John Q. Public, represented the beleaguered American taxpayer. The character appeared first in The Chicago Daily News, the paper on which Mr. Shoemaker began his career in 1922.