Trevor Nelsson is an attorney living in Pawnee. He has short, light-red hair and is typically well-dressed. The character is played by Marc Evan Jackson.

Trevor is first seen representing the interests of Dr. Saperstein in his attempts to strong arm Tom Haverford into signing over his company Rent-A-Swag.

Trevor later advises Ron Swanson on the preparation of a will. He is shown to have little patience for Ben Wyatt, or jokes.

In Season 7, it is revealed that Trevor is an attorney with the law firm Fwar, Dips, Winshares, Gritt, Babip, Pecota, Vorp, and Eckstein. Trevor was shown to be working as legal counsel for the Newport Family Trust.

In "One Last Ride", Trevor is shown to be working as counsel for the Very Good Building & Development Co. on the day that Ron resigns in 2022.