He was initially appointed to the court by Maryland Governor John Lee Carroll in 1878 and elected to the position in November 1879.
He was also an editor for several newspapers, such as the Frederick Examiner, the Federal Gazette and the Baltimore Chronicle, for which he was also the proprietor.
In a letter to mutual acquaintance Joseph Snodgrass, Edgar referred to his cousin Neilson: "I believe him to be the bitterest enemy I have in the world.
"[1] On October 3, 1849, Edgar Allan Poe was found semiconscious at Ryan's Inn and Tavern.
Neilson attempted to visit Edgar in the hospital and subsequently wrote several letters containing information about his cousin's death.