In 1822, Andrus moved to Macomb County, Michigan Territory, with his father.
[2] In 1867, Andrus served as a delegate from Macomb County in the Michigan constitutional convention.
Under President Ulysses S. Grant, Andrus served as Assessor of Internal Revenue in the 5th congressional district.
[3] On March 21, 1881, State Senator John T. Rich resigned to fill the vacancy left in the United States House of Representatives left by Congressman Omar D. Conger's resignation.
[1] In 1895, Andrus was appointed by Governor John T. Rich to the Macomb County jury commission for a term of two years.