Englund was born in Boden and studied caretaking for two years and then humanistic subjects for another two years in secondary school. He was then conscripted and served 15 months in the Swedish Army at the Norrbotten Regiment located in Boden. He was politically active in his youth and supported the FNL.
Englund studied archaeology, history, and theoretical philosophy at Uppsala University, completing a bachelor's degree in 1983, after which he began doctoral studies in History. He was awarded his Ph.D. in 1989 for his dissertation Det hotade huset (English title in the dissertation abstract: A House in Peril) (1989), an investigation of the worldview of the 17th-century Swedish nobility. During his period as a doctoral student, he had also worked for some time for the Swedish Military Intelligence and Security Service ("MUST"), and the year before receiving his doctorate he had published the bestselling Poltava, a detailed description of the Battle of Poltava, where the troops of Swedish king Charles XII were defeated by the Russian army of Tsar Peter I in 1709.
Englund has received the August Prize (1993) and the Selma Lagerlöf Prize for Literature (2002). He was elected a member of the Swedish Academy in 2002. On 1 June 2009 he succeeded Horace Engdahl as the permanent secretary of the Academy.
Englund writes non-fiction books and essays, mainly about history, and especially about the Swedish Empire, but also about other historical events. He writes in a very accessible style, providing narrative details usually omitted in typical books about history. His books have gained popularity and are translated into several languages, such as German and Czech.
In 2009, to perhaps distance himself from Engdahl, the previous Nobel secretary, Dr. Englund, "criticized the jury panel as being too "Eurocentric,'" and "told The Associated Press that it was easier for Europeans to relate to European literature."
- Holowczyn: Battle of the Moscow Road (boardgame, 1980)
- Peter the Great (boardgame, 1980)
- Poltava ("Poltava") (1988)
- Det hotade huset ("A House in Peril") (1989)
- Förflutenhetens landskap ("The Landscape of Times Past") (1991), collection of essays
- Ofredsår ("Years of War") (1993), Sweden during Thirty Years' War with Erik Dahlberg at the centre of the book
- Brev från nollpunkten ("Letters from Ground Zero") (1996), collection of essays about modern history
- Den oövervinnerlige ("The Invincible") (2000), on Sweden’s period as a Great Power. Sequel to Ofredsår
- Erik Lönnroth : inträdestal i Svenska akademien (2002)
- Tystnadens historia och andra essäer (2003)
- Jag skall dundra (2005)
- Tystnadens historia ("History of Silence") (2004), collection of essays
- Spegelscener : minnesfragment från fyra krig (2006)
- Silvermasken ("The Silver Mask") (2006), a short biography of Queen Kristina of Sweden
- Stridens skönhet och sorg ("The Beauty and the Sorrow") (2008), a biography-based book about 19 people who lived during World War I
- Det stora svalget : en finlandssvensk i första världskriget (2010)