He was admitted to the Texas bar in 1950, and to practice before the Supreme Court of the United States in 1956. From 1951 to 1961, Clark was an associate and partner in the law firm of Clark, Reed and Clark.
In 1967, President Johnson nominated him to be Attorney General of the United States, he was confirmed by congress and took the oath of office March 2,. There is speculation that Johnson made the appointment on the expectation that Clark's father, Associate Justice Tom C. Clark, would resign from the Supreme Court to avoid a conflict of interest. Johnson wanted a vacancy to be created on the Court so he could appoint Thurgood Marshall, the first African American justice. The elder Clark resigned from the Supreme Court on June 12, 1967, creating the vacancy Johnson desired.
Clark served as Attorney General until Johnson's term as President ended on January 20, 1969.
Clark played an important role in the history of the American Civil Rights movement. During his years at the Justice Department, he
As Attorney General during part of the Vietnam War, Clark oversaw the prosecution of the Boston Five for “conspiracy to aid and abet draft resistance.” Four of the five were convicted, including pediatrician Dr. Benjamin Spock and Yale chaplain William Sloane Coffin Jr.
In 1974 he was the Democratic Party's candidate for the United States Senate from New York, losing to Jacob Javits. In 1976, Clark again sought the Democratic nomination for U.S. Senate, but was a distant third in the primary behind Daniel Patrick Moynihan, (the winner), and Congresswoman Bella Abzug.
More recently, Clark has become controversial for his political views and publications. While mildly denouncing the September 11,terrorist attacks]] in New York City and Washington D.C. in 2001, he has also strongly opposed any retaliation against Afghanistan as well as against Al-Qaeda. He has been a strong opponent of the War on Terrorism in Afghanistan and the rest of the world from the very beginning.
In 1991, Clark accused the administration of President George H. W. Bush and "others to be named" of "crimes against peace, war crimes" and "crimes against humanity" for its conduct of the Gulf War against Iraq and the ensuing sanctions; in 1996, he added the charges of genocide and the "use of a weapon of mass destruction". Similarly, after the 1999 NATO bombing of the Federal Republic of Yugoslavia Ramsey charged and "tried" NATO on 19 counts and issued calles for its dissolution.
Clark is affiliated with VoteToImpeach, an organization advocating the impeachment of George W. Bush. He has been an opponent of both 1991 and 2003 Persian Gulf War conflicts. "Impeachment is the most important issue facing Constitutional government in the United States. Impeachment will determine whether the American people will hold the Bush administration accountable for its High Crimes and Misdemeanors". Clark is the founder of the International Action Center. It holds significant overlapping membership with the Workers' World Party. Clark and the IAC helped found the protest organization A.N.S.W.E.R. (Act Now to Stop War and End Racism).
Ramsey Clark has been criticized for some of the people he agreed to defend; this criticism has been exacerbated by some statements Clark has made in defense of his clients.
In 2004 Clark joined a panel of about 20 prominent Arab and one other non-Arab lawyer to defend Saddam Hussein in his trial before the Iraqi Special Tribunal. Clark appeared before the Iraqi Special Tribunal in late November 2005 arguing "that it failed to respect basic human rights and was illegal because it was formed as a consequence of the United States' illegal war of aggression against the people of Iraq. Clark said that unless the trial was seen as "absolutely fair", it would "divide rather than reconcile Iraq". Christopher Hitchens claimed that Clark was admitting Hussein's guilt when Clark reportedly stated in a 2005 BBC interview: "He [Saddam] had this huge war going on, and you have to act firmly when you have an assassination attempt".
Clark was not alone in criticizing the Iraqi Special Tribunal's trial of Saddam Hussein, which drew intense criticism from international human rights organizations. Human Rights Watch called Saddam's trial a "missed opportunity" and a "deeply flawed trial, and the UN Working Group on Arbitrary Detention found the trial to be unfair and to violate basic international human rights law. Among the irregularities cited by HRW, were that proceedings were marked by frequent outbursts by both judges and defendants, that three defense lawyers were murdered, that the original chief judge was replaced, that important documents were not given to defense lawyers in advance, that paperwork was lost, and that the judges made asides that pre-judged Saddam Hussein. One of those outburst occurred when Clark was ejected from the trial after passing the judge a memorandum stating that the trial was making "a mockery of justice". The Chief Judge Raouf Abdul Rahman shouted at Clark, "No, you are the mockery... get him out, out".
On March 18, 2006, Clark attended the funeral of Slobodan Milošević. He declared: "History will prove Milošević was right. Charges are just that, charges. The trial did not have facts." He compared the trials of Slobodan Milošević and Saddam Hussein, stating: "both trials are marred with injustice, both are flawed." He also described Slobodan Milošević and Saddam Hussein as "[b]oth commanders" who "were courageous enough to fight more powerful countries.
On September 1, 2007, in New York, Clark, 79, called for detained Filipino Jose Maria Sison’s release and pledged assistance by joining the latter’s legal defense team headed by Jan Fermon. Clark doubted Dutch authorities’ validity and competency, since the murder charges originated in the Philippines and had already been dismissed by the country's Supreme Court.
Former Attorney General and peace and social justice activist for his commitment to civil rights, his opposition to war and military spending and his dedication to providing legal representation to the peace movement, particularly, his efforts to free Leonard Peltier. He was awarded the Peace Abbey Courage of Conscience on October 15, 1992.
In August, 2006, Clark spoke at an International Islamic Conference for Peace and Awareness in Baltimore, Maryland, which critics described as a "propaganda" conference involving the holocaust denial group Institute for Historical Review in alliance with Islamic extremists. Clark's address focused on the wars in Afghanistan and Iraq.