In 1829, he came to the United States. He learned carpentry and construction in Ohio and ended up in Little Rock. One of his jobs was as the finishing contractor on the State Capitol building, now known as the Old State House.
He later gave up carpentry and became an attorney. (It is said that he did so after becoming embroiled in a legal dispute arising from one of his construction jobs.) Wassell also served as a judge.
In 1868, he was appointed Mayor of Little Rock by President Andrew Johnson. He is Little Rock’s only Mayor to have served through a military appointment. Mayor Wassell died in January 1881 and is buried at Mount Holly Cemetery along with his wife and other family members. One of his grandsons, Samuel M. Wassell also served as Mayor of Little Rock.