Southworth was born into slavery and brought to the Oregon Territory by his enslaver, from whom he bought his freedom with cash, earned chiefly from his expertise with the fiddle or violin.

Southworth lived or worked near Monroe, Jacksonville, and Buena Vista before settling along a small tributary of the Alsea River, where he farmed and engaged in other enterprises and civic undertakings.

[4] While returning from Jacksonville to Monroe, Lewis encountered soldiers fighting in the Rogue River Wars who threatened to confiscate his rifle.

To avoid proceeding unarmed, Southworth joined the militia, fought against the Native American tribes commonly grouped under the designation of Rogue River Indians, and was subsequently wounded in a skirmish in 1856.

Under provisions of the Homestead Act of 1862, Southworth acquired a land grant near the Alsea River upstream of Waldport, where he farmed, fished, hunted, built a sawmill, became active in community affairs, and played the fiddle for dances.

[7] After Cooper died in 1901,[3] Southworth moved to Corvallis, where he bought and lived in a house at the corner of Southwest Fourth Street and Adams Avenue.