Mahan briefly left at the end of the month to conduct Combat Direction Finding System testing at sea.

The next few months saw events including Command Assessment of Readiness and Training (CART), ammunition onload at Yorktown Naval Weapons Station, Tailored Ship’s Training Availability (TSTA), Industrial Hygiene Survey, Combat Systems Ship’s Qualification Trial (CSSQT), evaluation at the Atlantic Undersea Test and Evaluation Center (AUTEC), MISSILEX, Naval Surface Fire Support (NSFS) qualification, VANDALEX, Final Conduct Trial, a post-Shipyard Availability Conference, and a recruiting video shoot, all before the end of July.

Mahan departed Portland on 16 November, and during the transit back to Norfolk, conducted her first underway replenishment, with USNS Big Horn.

Mahan crew members worked with their Australian counterparts in cleaning the Soldiers, Sailors, Airmen, and Marines Center in midtown Manhattan.

Crew members were able to pay their respects by conducting a wreath laying ceremony at the World Trade Center.

[6] USS Mahan began a Selected Restricted Availability (SRA) at the BAE Systems Ship Repair shipyard in Norfolk, Virginia on 6 January 2010.

The extensive upgrades and installations received during this time focused on improving the ship's Command and Control capability.

Mahan participated in the USS Kearsarge Amphibious Readiness Group's COMPTUEX in July, resulting in certification for maritime support operations.

Later that month, Mahan visited Newport, Rhode Island to be the Surface Warfare Officer's School (SWOS) Ship for the week of 15–19 August.

[9] Mahan began a Selected Restricted Availability (SRA) at the Marine Hydraulics International shipyard in Norfolk, Virginia, on 26 October 2011.

Following a command investigation, 13 Mahan sailors were awarded non-judicial punishment for illegal drug use during a captain's mast on 4 April 2012.

Later in October, Mahan was the host ship for the United States Naval Academy Homecoming Weekend in Annapolis, Maryland.

Master-At-Arms Second Class Mark Mayo who was on duty as the Chief of the Guard, dove in front of the ship's Petty Officer of the Watch to shield her from the gunman.

According to the officials speaking anonymously to Reuters, a helicopter dropped a smoke float and the destroyer launched flares but the boats continued at speed.

The trident at the center of the shield symbolizes the ship's warfare capabilities while underscoring the importance of a strong navy.

[citation needed] The crest consists of a red compass enclosed in a gold annulet surrounded by a wreath.

The compass rose and annulet represent Mahan's influence of sea power, its strategy and geopolitical importance worldwide.

During USS Arleigh Burke's commissioning, Admiral Burke issued a challenge to his sailors: “This ship is built to fight; you’d better know how.” The coat of arms in full color as in the blazon, upon a white background enclosed within a dark blue oval border edged on the outside with a gold rope and bearing the inscription "USS MAHAN" at the top and "DDG 72" in the base all gold.