The historical marker seems to be taken from the quote attributed to Dean Alfange:

“My Creed

I do not choose to be a common man,
It is my right to be uncommon … if I can,
I seek opportunity … not security.
I do not wish to be a kept citizen.
Humbled and dulled by having the
State look after me.
I want to take the calculated risk;
To dream and to build.
To fail and to succeed.
I refuse to barter incentive for a dole;
I prefer the challenges of life
To the guaranteed existence;
The thrill of fulfillment
To the stale calm of Utopia.
I will not trade freedom for beneficence
Nor my dignity for a handout
I will never cower before any master
Nor bend to any threat.
It is my heritage to stand erect.
Proud and unafraid;
To think and act for myself,
To enjoy the benefit of my creations
And to face the world boldly and say:
This, with God’s help, I have done
All this is what it means
To be an Entrepreneur.”

― Dean Alfange

Using this makes American and entrepreneur synonymous, which sounds about right.

The American’s Creed is also known as the following, written by William Tyler Page:

I believe in the United States of America as a government of the people, by the people, for the people; whose just powers are derived from the consent of the governed, a democracy in a republic, a sovereign Nation of many sovereign States; a perfect union, one and inseparable; established upon those principles of freedom, equality, justice, and humanity for which American patriots sacrificed their lives and fortunes.

I therefore believe it is my duty to my country to love it, to support its Constitution, to obey its laws, to respect its flag, and to defend it against all enemies.

–Written 1917, accepted by the United States House of Representatives on April 3, 1918.