[7] His mother, Rebecca "Beckie" Ezekkiels, was the daughter of Romanian Jews; Mark Clark was baptized Episcopalian as a cadet at the United States Military Academy at West Point, New York.

[10][11][12] He graduated alongside young men such as Matthew Ridgway, J. Lawton Collins, (both of whom later became U.S. Army Chief of Staff) Ernest N. Harmon, William W. Eagles, Norman Cota, Laurence B. Keiser, John M. Devine, Albert C. Smith, Frederick A. Irving, Charles H. Gerhardt, Bryant Moore and William K. Harrison.

[14][11] In late April 1918, shortly before Clark's 22nd birthday and over a year after his graduation from West Point, he arrived on the Western Front, to join the American Expeditionary Forces (AEF).

[16] Captain Clark recovered from his injuries within six weeks, but was graded unfit to return to the infantry,[16] being transferred to the Supply Section of the newly formed First Army.

In this position he served with Colonel John L. DeWitt, and supervised the daily provision of food for the men of the First Army, which earned Clark recognition at the higher levels of command.

Among his classmates there were Matthew Ridgway, Walter Bedell Smith and Geoffrey Keyes, all of whom he would serve with during World War II.

[19] On 4 August 1941, Clark, skipping the rank of colonel, was promoted two grades to the temporary rank of brigadier general as the U.S. Army geared up for entry into World War II, and made Assistant Chief of Staff (G-3) at General Headquarters, United States Army, in Washington, D.C.[14][4] In January 1942, a month after the Japanese attack on Pearl Harbor and the American entry into World War II, Clark was appointed Deputy Chief of Staff of Army Ground Forces (AGF), commanded by Lieutenant General Lesley J. McNair, and in May 1942 became its Chief of Staff.

Many officers, most notably Major General George S. Patton Jr., who was both older and senior to Clark, and was then commanding I Armored Corps, came to resent him, believing he had advanced too quickly.

The invasion, despite good initial progress, was nearly defeated over the next few days by numerous German counterattacks, and Major General Dawley, the VI Corps commander, was sacked and replaced by Major General John P. Lucas, who himself was later sacked and replaced after his perceived failure during Operation Shingle.

[24] Despite this Clark was later awarded the Distinguished Service Cross (DSC), the citation for which reads: The President of the United States of America, authorized by Act of Congress 9 July 1918, takes pleasure in presenting the Distinguished Service Cross to Lieutenant General Mark Wayne Clark (ASN: 0–5309), United States Army, for extraordinary heroism in connection with military operations against an armed enemy while Commanding the 5th Army, in action against enemy forces on 14 September 1943 at Salerno, when the FIFTH Army's bridgehead was threatened by an enemy counterattack.

General Clark personally instilled determination and courage in his men, under artillery and machine gun fire at the front line.

By his magnificent display of leadership, courage and determination during a critical phase of the battle, front line troops were inspired to hold at all costs and subsequently to initiate steady advance.

[25]The Fifth Army, by now composed of five American divisions (the 3rd, 34th, 36th and 45th Infantry, along with the 82nd Airborne) and three British divisions (7th Armoured, 46th and 56th Infantry), operating alongside the British Eighth Army, under General Bernard Montgomery, subsequently advanced up the spine of Italy, and captured the Italian city of Naples on 1 October 1943, and crossed the Volturno Line in mid-October.

This was under direct orders from his superior, British General Sir Harold R. L. G. Alexander, Commander-in-Chief (C-in-C) of the Allied Armies in Italy (AAI).

[26] Clark and his chief of staff, Major General Alfred Gruenther, remained unconvinced of the military necessity of the bombing.

American military historian Carlo D'Este called Clark's choice to take the undefended Italian capital of Rome, after Operation Diadem and the breakout from the Anzio beachhead, in early June, rather than focusing on the destruction of the German 10th Army, "as militarily stupid as it was insubordinate".

[30] Although Clark described a "race to Rome" and released an edited version of his diary for the official historians, his complete papers became available only after his death.

[32] Next month, during the air raid he ordered on Monte Cassino abbey, 16 bombs were mistakenly dropped at the Fifth Army headquarters compound then 17 miles (27 km) away from there, exploding yards from his trailer while he was at his desk inside.

[34] In December 1944 Clark succeeded Alexander as commander of the AAI, renamed the 15th Army Group, and Alexander was made the Supreme Commander of the AFHQ in the Mediterranean, replacing Field Marshal Sir Henry Maitland Wilson, who himself was called to Washington to replace Field Marshal Sir John Dill as head of the British Joint Chiefs of Staff.

Clark was promoted to the four-star rank of acting general on 10 March 1945, aged 48, the youngest in the United States Army.

Later in 1945, as Commander in Chief of US Forces of Occupation in Austria, Clark gained experience negotiating with communists, which he would put to good use a few years later.

Clark served as deputy to the US Secretary of State in 1947 and attended the negotiations for an Austrian treaty with the Council of Foreign Ministers in London and Moscow.

The petition read: Be it resolved, that the men of the 36th Division Association petition the Congress of the United States to investigate the river Rapido fiasco and take the necessary steps to correct a military system that will permit an inefficient and inexperienced officer, such as General Mark W. Clark, in a high command to destroy the young manhood of this country and to prevent future soldiers being sacrificed wastefully and uselessly.

[citation needed] In this capacity he also served as Supreme Commander for the Allied Powers, overseeing all U.S. forces in the postwar occupation of Japan.

[citation needed] Members of the Clark Task Force were Admiral Richard L. Conolly, a former Deputy Chief of Naval Operations; Ernest F. Hollings, the speaker pro tempore of South Carolina's House of Representatives; California businessman Henry Kearns; Edward V. Rickenbacker, World War I flying ace and president of Eastern Air Lines; and Donald S. Russell, a former Assistant Secretary of State.

The task force first met in early November 1954 and in May 1955 submitted a top-secret report for the president and another that was unclassified for the Hoover Commission and Congress.

[44] In 1962, Clark was elected an honorary member of the South Carolina Society of the Cincinnati in recognition of his outstanding service to his country.

From 1949 to August 17, 2010, the Mark Clark Bridge in Washington connected Camano Island with the adjacent town of Stanwood on the mainland.

Two locations in the Brazilian state of Rio de Janeiro—the Academia Militar das Agulhas Negras in Resende, and a street in São Gonçalo—have been named after Clark.

[51] In the neighborhood of Santa Catarina, in the city of São Gonçalo, located in the State of Rio de Janeiro – Brazil, there is a street called Gen. Mark Clark.