[3] On June 26, 1902, or July 8, 1902,[7] Porter received the Medal of Honor for the Battle of Chickamauga as detailed in the citation noted below.

[3][8] From April 4, 1864, to July 25, 1866, Porter was aide-de-camp to General Ulysses S. Grant with the grade of lieutenant colonel in the regular army.

[9] From July 25, 1866, to March 4, 1869, Porter was aide-de-camp to General Ulysses S. Grant with the grade of colonel in the regular army.

[3] Porter had refused to take a $500,000 vested interest bribe from Jay Gould, a Wall Street financier, in the Black Friday gold market scam.

However, during the Whiskey Ring trials in 1876, Treasury Solicitor Bluford Wilson claimed that Porter was involved with the scandal.

Ambassador to France from 1897 to 1905,[3] paying for the recovery of the body of John Paul Jones and sending it to the United States for re-burial.

He was also a member of the Military Order of the Loyal Legion of the United States, the Sons of the American Revolution and a Hereditary Companion of the Military Order of Foreign Wars by right of his descent from Lieutenant Colonel Andrew Porter who served in the American Revolution.

[13] He died in Manhattan, New York and is interred at the Old First Methodist Church Cemetery in West Long Branch, New Jersey.