As Governor, Olden supported President Abraham Lincoln and the national war effort but favored union and reconciliation with the South above all else; before the war, he argued slavery was properly understood as the sole regulatory province of the states, and he later opposed Lincoln's Emancipation Proclamation.

[1] Upon his graduation from Lawrenceville, Olden worked in his father's store for some time before joining the mercantile firm of Matthew Newkirk.

[1][2] After his uncle died and bequeathed Olden a large estate, he returned to Princeton, where he constructed Drumthwacket as his personal residence.

[1] In 1859, the Opposition Party, a loosely knit organization of former Whigs, Know Nothings, and Republicans, nominated Olden for Governor of New Jersey.

[1] As Governor during the last days before the American Civil War, Olden was an advocate for compromise and reconciliation with the South.

[1] After the Battle of Fort Sumter and the outbreak of war, New Jersey and Olden shifted in decided favor of the Union.

He called a special legislative session, at which he asked for the creation of four regiments for coastal defense of southern New Jersey on both the river and ocean fronts.

He was the first President of the Loyal National League of New Jersey, a non-partisan organization dedicated to bringing together supporters of the war.