Muslims have fought in all major United States conflicts, including the War of 1812, the American Civil War, World War I, World War II, and the Vietnam War. More recently, they have served in the Gulf War, Iraq War, and the War in Afghanistan.
On December 14, 1993, the Army Chief of Chaplains requested that an insignia be created to represent Muslim chaplains, with the design (a crescent) being completed January 8, 1994.
Muslims have fought and died in World War II and the Vietnam War. Some Muslim Americans served in World War II in North Africa, Europe, and Asia. Additionally, at least 12 Muslims are known to have died in the Vietnam War.
An African slave by the name of Bilali Muhammad defended Georgia's Sapelo Island from British attack during the War of 1812. His group consisted of 80 slaves who were mostly Muslim and were armed with muskets.
291 Muslims are known to have fought during the Civil War. Some sources claim that highest ranking Muslim officer during the War was Captain Moses Osman, the son of Robert and Catherine Osman. However, Moses Osman was confirmed in the Zion German Lutheran Church in 1843 in Harrisburg, Pennsylvania. 
The most highly ranked Muslim in the War may be Nicholas Said. He came to the United States in 1860 and he found a teaching job in Detroit. In 1863, Said enlisted in the 55th Massachusetts Colored Regiment in the United States Army and rose to the rank of sergeant. He was later granted a transfer to a military hospital, where he gained some knowledge of medicine. His Army records state that he died in Brownsville, Tennessee, in 1882. Another Muslim soldier from the Civil War was Max Hassan, an African who worked for the military as a porter.
Abdullah Igram, a Muslim-American WWII veteran, campaigned for Islam to be an option in servicemembers' religious identification. His organization provided additional tags which soldiers were allowed to wear in 1953, and by then dog tags included codes for 'other' and 'prefer not to say'. By the Vietnam War, personnel could use a wide list of spelled out religion names. 
Following 9/11, Muslims experienced an increase in verbal and physical harassment, despite efforts made by the White House. George W. Bush met with leaders of the Sikh community to discuss violence and prejudice that was being directed towards them as well after 9/11. South Asians and Arabs were targeted under discriminatory acts and hate crimes due to perceived affiliation with Islam. After 9/11, 6,024 served in the military in the Iraq and Afghanistan wars, with at least 15 or more being killed overseas. As of December 2015, 5,896 of the 1.3 million active members of the US military self-identify as Muslim, or roughly 0.45%. Practicing Muslims, in accordance with US military policy, are required shave their beards and are often unable to obtain food which doesn't conflict with their dietary restrictions. Muslim American involvement in the US military has come under increased attention after events such as the September 11 attacks terrorist attacks, 2009 Fort Hood shooting, and Khizr Khan 2016 Democratic National Convention speech.
Humayun Khan was a Pakistani-American born in the United Arab Emirates on September 9, 1976, to Pakistani parents. After graduating from the University of Virginia in 2000, he joined the U.S. Army's 201st Forward Support Battalion, 1st Infantry Division. Throughout his four years of service, he rose in ranks to become an officer in the U.S. army before being killed by a car bomb June 8, 2004, saving the lives of his fellow soldiers. President Donald Trump’s temporary immigration ban based on a list of terror linked countries (created under the Obama administration) brought Khan's parents, Khizr and Ghazala Khan, into the public spotlight as they addressed Trump at the Democratic National Convention in 2016. Speaking out to defend their son, and others who died in the American military, created an "unexpected and potentially pivotal flash point in the general election" 
Colonel Douglas Burpee is a retired U.S. Marine, having flown helicopters for 27 years. Burpee was born Episcopalian but converted to Islam when he was 19 in the late 1970s while attending the University of Southern California. He was accepted into the Officers Candidates' School in Quantico, VA, after graduation. At the end of his service, Burpee was the highest ranking Muslim in the U.S. Marine Corps.
Muslim Chaplain insignia, Army
Muslim Chaplain insignia, Navy
Muslim Chaplain insignia, Air Force