Of American-English origin, the phrase to go from zero to hero, and its variants, mean: to experience a sudden increase in popularity or success, especially having previously been in a position of low achievement or esteem.

However, long before the phrase came into use, the Irish poetess Mary Monck (née Molesworth – 1677?-1715) had used a similar rhyme, with the same sense of zero—this is her text, as published in Poems by Eminent Ladies (London: Printed for R. Baldwin, 1755):

On a ROMANTICK LADY.

ΤHIS poring over your Grand Cyrus
Must ruin you, and will quite tire us.
It makes you think, that an affront ’tis,
Unless your lover’s an Orontes,
And courts you with a passion frantick,
In manner and in stile romantick.
Now tho’ I count myself no Zero,
I don’t pretend to be an hero.
Or a by-blow of him that thunders,
Nor are you one of the sev’n wonders.
But a young damsel very pretty,
And your true name is Mistress Betty.

These are, in chronological order, the earliest occurrences of the phrase to go from zero to hero, and variants, that I have found:

1-: From Address Before the Second Biennial Convention of the World’s Woman’s Christian Temperance Union, and the Twentieth Annual Convention of the National Woman’s Christian Temperance Union. By their President, Frances E. Willard, World’s Columbian Exposition, Chicago, Illinois, U. S. A., Art Institute Building, October 16^th to 21^st 1893 (Chicago: Woman’s Temperance Publishing Association, 1893)—Frances Elizabeth Willard (1839-1898) was a U.S. educator and social reformer dedicated to the causes of temperance and women’s suffrage:

The history of the reformer, whether man or woman, on any line of action is but this: when he sees it all alone he is a fanatic; when a good many see it with him they are enthusiasts; when all see it he is a hero. The gradations are as clearly marked by which he ascends from zero to hero, as the lines of latitude from the North Pole to the Equator.

(In the following years, several U.S. newspapers reprinted this paragraph by Frances E. Willard, which may have popularised the phrase.)

2-: From The Scioto Gazette (Chillicothe, Ohio) of Saturday 4^th June 1927:

Tabernacle Baptist Church

Bible School, 9:15 a. m. Mr. J. R. Robinson, Supt. Classes for all ages. Morning Worship 10:30. Sermon topic, “From Zero to Hero.” Communion service. B. Y. P. U. 6:30 p. m. A meeting for all young people. Evening Service, 7:30 p. m. Preceded by 15 minutes Prayer Service by Church Deacons and Officers. Sermon subject, “The Valley of Dry Bones.” You are cordially invited to attend and worship with us.

3-: From Social and General, published in The Lexington Advertiser (Lexington, Mississippi) of Thursday 17^th April 1930:

Study Club Program
“FROM ZERO TO HERO”
1923 – 1929

1. Zaglul Pasha—Mrs. S. L. Burwell.
2. Social Customs—Mrs. E. F. Noel.
3. Modern Literature—Mrs. G. G. Ash.
4. Tut-Ank-Amen—Mrs. L. B. Durden.
The Club to meet with Mrs. Ben Beall, Jr., May 7^th, at 3 p.m.

4-: From the account of a baseball match between the Fort Worth Cats and the Beaumont Exporters, published in the Fort Worth Star-Telegram (Fort Worth, Texas) of Monday 16^th June 1930:

Tom Holley, who kicked in the lone Cat tally, changed himself from zero to hero in the same afternoon by driving in the first two Exporter markers.

5-: From the title of the following drawing, published in the New Britain Herald (New Britain, Connecticut) of Tuesday 14^th October 1930:

Hack Comes Back, or From Zero to Hero

HACK WILSON – OF THE CUBS – THE NEW HOME RUN KING, AND MOST VALUABLE PLAYER IN THE NATIONAL LEAGUE
LAST YEAR – THE ‘GOAT’ OF THE WORLD’S SERIES . . . “OH DEAR ME!”
TODAY . . . THE DARLING OF THE NATIONAL LEAGUE!

Conversely, the phrase to go from hero to zero, and its variants, mean: to suffer a sudden decline in popularity or success; to experience a fall from grace.

These are, in chronological order, the earliest occurrences of this phrase that I have found:

1-: From The Bossier Banner (Benton, Louisiana) of Thursday 30^th November 1899—with a pun on zero in the sense of the temperature corresponding to 0°:

The Kansas thermometer has now dropped from hero to zero.

2-: From Hero to Zero is the title of a short story by James H. Borland—copyright, 1911, by The Shortstory Publishing Company. It is the story of peace-loving Lovejoy, who gets a bump on the head that turns him into a bellicose man, then gets a second bump that returns him to his former self.

3-: From Spirit of the New Jersey Press, published in the Camden Post-Telegram (Camden, New Jersey) of Wednesday 6^th October 1915:

FROM HERO TO ZERO.

From the Long Branch Record:
The ups and downs of politics are proverbial, but did anyone else ever go up so fast and come down quite so quickly as Kinkead? From State hero to political zero in a few weeks is at least unprecedented in Jersey political history.

4-: From the Elmira Star-Gazette (Elmira, New York) of Monday 24^th November 1919:

SHORTEST STEP.

The shortest step
In the world is
From hero to zero.

5-: From Missing Links, by ‘Link’, published in The Frederick Leader (Frederick, Oklahoma) of Saturday 14^th May 1921:

It isn’t very far from hero to zero.