In 1866, he became a Principal of Woodstock Academy and taught there for several years. Afterwards, he began practicing law on the Shenandoah Circuit Court, serving as both Commissioner in Chancery and Commissioner of Accounts.[2] He formed a partnership with Henry C. Allen.[6]
In 1887, he was chosen as the Democratic candidate for Shenandoah in the Virginia House of Delegates, and held the post for several years.[7] He was offered the nomination for a fourth term in office, but declined.[6]
Personal life
On February 20, 1862, he married Annie Ott (died June 1905). They had five daughters (Ella, Lucy, Sue, Annie, and another) and two sons (Mark W. and Philip). He was a Presbyterian.[2]
On the afternoon of March 4, 1907, Magruder suffered a stroke while working in his office. He was moved home, where he died later that evening. He was buried in Massanutten Cemetery in Woodstock.[2]