Mattis was born in Pullman, Washington on September 8, 1950. He graduated from Columbia High School, Richland, Washington, in 1968 and enlisted in the United States Marine Corps in 1969. He later earned a Bachelor of Arts degree in history from Central Washington University and was commissioned a second lieutenant through ROTC on January 1, 1972. Mattis during his service years was considered something of an intellectual among the upper ranks, with his personal library numbering more than a thousand volumes. Major General Robert H. Scales (ret.)(PhD), described him as "....one of the most urbane and polished men I have known." Reinforcing this intellectual persona was the fact that he carried on his person a copy of the Meditations of Marcus Aurelius throughout his deployments.
As a lieutenant, Mattis served as a rifle and weapons platoon commander in the 3rd Marine Division. As a captain, he commanded a rifle company and a weapons company in the 1st Marine Regiment, then Recruiting Station Portland, Oregon, as a major.
Upon promotion to the rank of lieutenant colonel, Mattis commanded 1st Battalion, 7th Marines, which was one of Task Force Ripper's assault battalions during the Persian Gulf War.
As a colonel Mattis commanded 7th Marine Regiment. He led the 1st Marine Expeditionary Brigade as its commanding officer upon promotion to brigadier general. During the initial planning for the War in Afghanistan, Mattis led Task Force 58 in operations in the southern part of the country, becoming the first Marine officer to ever command a Naval Task Force in combat.
While serving in Afghanistan as a brigadier general, he was known as an officer who engaged his men with "real leadership". A young Marine officer named Nathaniel Fick cited an example of that leadership when he witnessed Mattis in a fighting hole talking with a sergeant and a lance corporal: "No one would have questioned Mattis if he'd slept eight hours each night in a private room, to be woken each morning by an aide who ironed his uniforms and heated his MREs (Meals, Ready-to-Eat). But there he was, in the middle of a freezing night, out on the lines with his Marines."
As a brigadier-general deployed to Afghanistan, Mattis came under intense scrutiny from Army and Air Force units in the vicinity of his Marines when he refused to send a CASEVAC team after ODA-574, an Army Green Beret team that had come in contact with enemy and, at one point had one soldier confirmed KIA, one missing and presumed KIA, and four others expected to die, regardless of whether or not they received medical aid. Units in Uzbekistan, four times further away from ODA-574's position than Mattis's Marines, were required to send in the CASEVAC. 
As a major general, Mattis commanded the 1st Marine Division during the 2003 invasion of Iraq and subsequent stability operations during the Iraq War. Mattis played key roles in combat operations in Fallujah, including negotiation with the insurgent command inside of the city during Operation Vigilant Resolve in April 2004, as well as participation in planning of the subsequent Operation Phantom Fury in November.
Following a U.S. Department of Defense survey that showed only 55% of American soldiers and 40% of U.S. Marines would report a colleague for abusing civilians, Mattis told U.S. Marines in May 2007 that "Whenever you show anger or disgust toward civilians, it's a victory for al-Qaeda and other insurgents." Reflecting an understanding of the need for restraint in war as key to defeating an insurgency, he added that "Every time you wave at an Iraqi civilian, al-Qaeda rolls over in its grave."
Mattis popularized the 1st Marine Division's motto "no better friend, no worse enemy", a paraphrase of the famous self-made epitaph for the Roman dictator Sulla, in his open letter to all men within the division for their return to Iraq. This phrase later became widely publicized during the investigation into the conduct of Lieutenant Ilario Pantano, a platoon commander serving under Mattis.
He also was noted for a willingness to remove senior leaders under his command at a time when the U.S. military seemed unable or unwilling to relieve under-performing or incompetent officers. During the division's push to Baghdad, Mattis relieved Colonel Joe D. Dowdy, regimental commander of Regimental Combat Team-1, and it was such a rare occurrence in the modern military that it made the front page of newspapers. Despite this, Mattis declined to comment on the matter publicly other than to say that the practice of officer relief remains alive, or at least "We are doing it in the Marines." Later interviews of Dowdy's officers and men revealed that "the colonel was doomed partly by an age-old wartime tension: Men versus mission in which he favored his men" while Mattis insisted on execution of the mission to seize Baghdad swiftly.
After being promoted to lieutenant general, Mattis took command of Marine Corps Combat Development Command. On February 1, 2005, speaking ad libitum at a forum in San Diego, he said "You go into Afghanistan, you got guys who slap women around for five years because they didn't wear a veil. You know, guys like that ain't got no manhood left anyway. So it's a hell of a lot of fun to shoot them. Actually, it's a lot of fun to fight. You know, it's a hell of a hoot. It's fun to shoot some people. I'll be right upfront with you, I like brawling." Mattis's remarks sparked controversy and General Michael Hagee, Commandant of the Marine Corps, issued a statement suggesting that Mattis should have chosen his words more carefully, but would not be disciplined.
The Pentagon announced on May 31, 2006 that Lieutenant General Mattis was chosen to take command of I Marine Expeditionary Force, based out of Marine Corps Base Camp Pendleton. On 11 September 2007, Secretary of Defense Robert Gates announced that President George W. Bush had nominated Mattis for appointment to the rank of general to command U.S. Joint Forces Command in Norfolk, Virginia. NATO agreed to appoint Mattis as Supreme Allied Commander Transformation. On 28 September 2007, the United States Senate confirmed Mattis's nomination, and he relinquished command of I MEF on 5 November 2007 to Lieutenant General Samuel Helland. Mattis was promoted to four-star general and took control of JFCOM/SACT on 9 November 2007. He transferred the job of SACT to French General Stephane Abrial on 9 September 2009, but continued in command of JFCOM.
In early 2010, Mattis was reported to be on the list of U.S. Marine generals being considered for selection to replace James T. Conway as the Commandant of the U.S. Marine Corps. In July, he was recommended by Defense Secretary Robert Gates for nomination to replace David Petraeus as commander of United States Central Command, and formally nominated by President Barack Obama on July 21. His confirmation by the Senate Armed Services Committee marked the first time Marines had held billets as commander and deputy commander of a Unified Combatant Command. He took command at a ceremony at MacDill Air Force Base on August 11.
As head of Central Command, Mattis oversaw the wars in Iraq and Afghanistan and was responsible for a region that includes Syria, Iran, Yemen. The Obama administration did not place much trust in Mattis, because he was perceived to be too eager for a military confrontation with Iran. He retired from the Marine Corps on May 22, 2013.
Mattis is a graduate of the U.S. Marine Corps Amphibious Warfare School, U.S. Marine Corps Command and Staff College, and the National War College. Mattis is also noted for his intellectualism and interest in military history, with a personal library that once included over 7,000 volumes, and a penchant for publishing required reading lists for Marines under his command. He has never been married and has no children. He is nicknamed "The Warrior Monk" because he devoted his life to studying and fighting war.
Since retirement, Mattis has worked for FWA Consultants and is an Annenberg Distinguished Visiting Fellow at the Hoover Institution. He also serves as a Member of the General Dynamics Board of Directors. He is a board member of Theranos, a Silicon Valley biotech company.
He is also the recipient of several civilian awards, to include:2009 - Center for National Policy’s Edmund S. Muskie Distinguished Public Service Award
2010 - Atlantic Council’s Distinguished Military Leadership Award.
2013 - World Affairs Council of Greater Hampton Roads “Ryan C. Crocker Global Citizen of the Year” Award
2014 - Marine Corps University Foundation Semper Fidelis Award
2014 - Washington College honorary doctor of laws degree
Mattis is portrayed by Robert John Burke in the 2008 HBO mini-series Generation Kill.