Is early America (pre-1877) defined by the concept of freedom?
There is no doubt that white male Americans enjoyed, by the middle eighteenth century, the highest average standard of living and the most wide-spread political freedoms of any people on the planet. This remained the case throughout the period in question. Indeed, territorial and economic expansion, accompanied by expansions of already broad voting rights during the first half of the nineteenth century made the United States a land of opportunity and freedom for many of its inhabitants.
Yet white freedom, undeniably a defining characteristic of American society from the colonial period to the Civil War, was achieved, indeed dependent upon, denying freedom to others. Slavery was essential to first the colonial and then the national economy, as cash crops represented the vast majority of exports for the developing nation. Indeed, during the colonial period, a significant proportion of Americans (most, if we include the British colonies in the West Indies) did not arrive seeking liberty or economic opportunity, but rather were brought here against their will, in the bottoms of slave ships. Furthermore, the territorial expansion of the first part of the nineteenth century, which had the effect of creating tremendous economic opportunities for whites, was driven by the desire for new lands on which to plant cotton, cultivated by blacks and forcibly taken from Native Americans.
So the short answer to this very complex question is that America from the colonial period to Reconstruction can certainly be defined by freedom. But the expanded freedoms available to many Americans depended on the denial of freedoms to others.