This is from Wikipedia  and Home of the Hero’s.
Seaman Sweeney is one more of the 19 double medal recipients.
Seaman Sweeney is the only black man to receive two Medals of Honor.

Robert Augustus Sweeney (February 20, 1853 – December 19, 1890) was a sailor in the United States Navy and is one of only nineteen servicemen, and the only African American, to receive the Medal of Honor twice, both for peace-time actions. 

Born on February 20, 1853, in Montreal, Canada, Sweeney immigrated to the United States and joined the Navy from New Jersey.[1][2] By October 26, 1881, he was serving as an ordinary seaman on the USS Kearsarge. While Kearsarge was anchored in Hampton Roads on that day, Seaman E.M. Christoverson fell from a Jacob’s ladder attached to the ship’s lower boom and landed in the water. Christoverson’s inability to swim, combined with a strong tidal current and rough seas, led to him quickly beginning to sink. Seeing this, Sweeney jumped overboard without hesitation and went to his aid. In his panic, Christoverson latched onto Sweeney and dragged him under the water. Sweeney was able to break free, but was grabbed and dragged under a second time. One of Kearsarge’s officers, Cadet Midshipman John B. Bernadon, then dove into the water and swam to help the men. Together, Sweeney and Bernadon were able to keep Christoverson afloat and, once their shipmates had thrown them a rope, pulled him back aboard ship. For this action, Sweeney was awarded his first Medal of Honor six days later, on November 1.[3]
On December 20, 1883, while serving on the USS Jamestown at the Brooklyn Navy Yard, he and a shipmate, Landsman J. W. Norris, jumped into the water and rescued A.A. George, who had fallen overboard. Both Sweeney and Norris were awarded the Medal of Honor the next year, on October 18, 1884, for this act.[1]
Sweeney died on December 19, 1890, at age 37 and was buried at Calvary Cemetery in Queens, New York.[2]

Medal of Honor citation

moh_navy_orig.gif (5895 bytes)moh_navy_orig.gif (5895 bytes)
The President of the United States
in the name of
The Congress
takes pleasure in presenting the
Medal of Honor
First Award – Peace Time Heroism
Second Award – Peace Time Heroism

Rank and organization: Ordinary Seaman, U.S. Navy.  Place and date: Hampton Roads, Virginia, 26 October 1881.   Born. 1853 Montreal, Canada. Accredited to: New Jersey. G.O. No.: 326, 18 October 1884.
Serving on board the U.S.S. Kearsarge, at Hampton Roads, Va., 26 October 1881, Sweeney jumped overboard and assisted in saving from drowning a shipmate who had fallen overboard into a strongly running tide.

Rank and organization: Ordinary Seaman, U.S. Navy.   Place and date: Navy Yard, NY, 20 December 1883.  Born. 1853 Montreal, Canada.Accredited to: New Jersey. G.O. No.: 326, 18 October 1884.
Serving on board the U.S.S. Jamestown, at the Navy Yard New York, 20 December 1883, Sweeney rescued from drowning A. A. George, who had fallen overboard from that vessel.