In 1775, inspired by the American Revolution, Peale moved from his native Maryland to Philadelphia, where he set up a painting studio and joined the Sons of Liberty.

During the American Revolutionary War, Peale served in the Pennsylvania Militia and the Continental Army, participating in several military campaigns.

Peale studied with West for three years beginning in 1767, afterward returning to North America and settling in Annapolis, Maryland.

He completed portraits of scores of historic figures, including Benjamin Franklin, John Hancock, Thomas Jefferson, Alexander Hamilton, James Mitchell Varnum, and George Washington.

The display of the mammoth bones entered Peale into a long-standing debate between Thomas Jefferson and Comte de Buffon.

Jefferson referenced the existence of these "mammoths" (which he believed still roamed northern regions of the continent) as evidence for a greater biodiversity in North America.

Peale's display of these bones drew attention from Europe, as did his method of re-assembling large skeletal specimens in three dimensions.

This system drew a stark contrast between Peale's museum and his competitors who presented their artifacts as mysterious oddities of the natural world.

At various times it was located in several prominent buildings, including Independence Hall and the original home of the American Philosophical Society.

Peale died on February 22, 1827, and was buried at St. Peter's Episcopal Church in Philadelphia alongside his wife Elizabeth DePeyster.

[15] A Renaissance man, Peale had expertise not only in painting but also in many diverse fields, including carpentry, dentistry, optometry, shoemaking, and taxidermy.

In 1802, John Isaac Hawkins patented the second official physiognotrace, a mechanical drawing device, and partnered with Peale to market it to prospective buyers.

[16] Around 1804, Peale obtained the American patent rights to the polygraph from its inventor John Isaac Hawkins, about the same time as the purchase of one by Thomas Jefferson.

Peale and Jefferson collaborated on refinements to this device, which enabled a copy of a handwritten letter to be produced simultaneously with the original.