Mitchell's mother, Mary (née Saad), was a textile worker who immigrated to the United States in 1920 from Bkassine, Lebanon, at the age of eighteen.

[9] After graduating from high school at the age of sixteen,[4] Mitchell attended Bowdoin College in Brunswick, Maine, where he worked several jobs and played on the basketball team.

After having performed well academically at Georgetown, Mitchell served as a trial attorney for the Antitrust Division of the United States Department of Justice in Washington from 1960 to 1962, and then as executive assistant to Senator Edmund S. Muskie from 1962 to 1965, where he first gained interest in the political world.

He lost in the general election to independent candidate James B. Longley, but was appointed United States Attorney for Maine by President Jimmy Carter in 1977.

Mitchell voted in favor of the bill establishing Martin Luther King Jr. Day as a federal holiday and the Civil Rights Restoration Act of 1987 (as well as to override President Reagan's veto).

In 1994, Mitchell turned down an offer of appointment by President Bill Clinton to the United States Supreme Court,[4] to replace the retiring Harry A. Blackmun so that he could continue helping with efforts in the Senate to pass significant health-care legislation.

He also was mentioned in both 2000 and in 2004 as a potential secretary of state for a Democratic administration, due to his role as Senate Leader and the Good Friday agreements.

[24] Mitchell led an American fact-finding commission initiated under President Bill Clinton in 2000 intended to find solutions for solving the situation between Israel and the Palestinians.

[25] Mitchell served as co-chairman (with Newt Gingrich) of the Congressionally mandated Task Force on the United Nations, which released its findings and recommendations on June 15, 2005, after having been formed that January.

The World Justice Project works to lead a global, multidisciplinary effort to strengthen the Rule of Law for the development of communities of opportunity and equity.

He first led an international body to review options for paramilitary arms decommissioning, which produced the Mitchell Principles that regulated access to subsequent all-party peace talks.

[29] On June 28, 2006, Disney announced that its board had elected one of its members, John Pepper Jr., former CEO of Procter & Gamble, to replace Mitchell as chairman effective January 1, 2007.

[30] In 2006, Mitchell was tapped by MLB Commissioner Bud Selig to lead an investigation into the use of performance-enhancing drugs by Major League Baseball players.

The investigation derived largely from charges against Barry Bonds, and revelations in the Bay Area Laboratory Co-Operative (BALCO) trials of Victor Conte and Greg Anderson.

Selig has said that revelations brought forth in the 2005 book Game of Shadows were, by way of calling attention to the issue, in part responsible for the league's decision to commission an independent investigation.

[31] Mitchell did however hold extensive meetings with several known steroid dealers, club attendants, personal trainers, and others who had ties to all players named in the report.

Even though the union that protects the players had pressured all but Giambi and Thomas into maintaining the culture of silence that had helped the drug problem remain a secret, there was plenty of other evidence against those named in his report.

This list includes names of Most Valuable Players and All-Stars, such as Roger Clemens, Andy Pettitte, Miguel Tejada, Denny Neagle, Paul Lo Duca, David Justice, Barry Bonds, Éric Gagné, Todd Hundley, Randy Velarde, and Benito Santiago.

The Los Angeles Times reported that Mitchell acknowledged that his "tight relationship with Major League Baseball left him open to criticism".

[35] Mitchell responded to the concerns by stating that readers who examined the report closely "will not find any evidence of bias, of special treatment of the Red Sox".

The choice of Mitchell allowed Obama to demonstrate the seriousness and sincerity of his intentions regarding the peace process, without forcing him to immediately embark on a specific initiative before conditions were yet ripe.

Mitchell began his meetings in Cairo on January 27, and Obama said his visit was part of the president's campaign promise to listen to both sides of the Israeli–Palestinian conflict and negotiate a peace deal.

[44] In June 2014, Mitchell was hired as a senior advisor at the public relations and advisory company Teneo,[45] a firm closely connected to the Clintons.

The papers included affidavits and depositions of key witnesses in a 2015 lawsuit that Giuffre filed against Epstein and his associate Ghislaine Maxwell.

[63] On April 10, 2018, Mitchell was awarded Freedom of the City of Belfast, alongside former president Bill Clinton in a ceremony at the Ulster Hall.