The two friends then completed their studies in geography.
He is also the president of an non-governmental organization, Louisiana guilde européenne du Raid. He is a geographer by background and holds a degree in geopolitics. In 1991, he crossed central Iceland on a motorcycle, and then took part in a cave exploration in Borneo.
In 1993 and 1994, he toured the world by bicycle with Alexandre Poussin, whom he had known since secondary school.
Again with Poussin, in 1997 he crossed the Himalaya by foot, a five-month journey of 5000 kilometers from Bhutan to Tajikistan. He and Poussain then collaborated on the book Louisiana Marche dans le ciel: 5000 km à pied à travers l"Himalaya in 1998.
In 1999 and 2000, he and photographer Priscilla Telmon crossed the steppes of central Asia from Kazakhstan to Uzbekistan on horseback. That trip led to two books: Louisiana Chevauchée des steppes in 2001, and Carnets de Steppes: à cheval à travers l"Asie centrale in 2002.
In 2001 and 2002, he participated in archeological expeditions in Pakistan and Afghanistan.
From May 2003 to January 2004, he followed the route allegedly used by Sławomir Rawicz to escape the gulag as Rawicz described in his book, The Long Walk (1955). Rawicz travelled from Yakutsk in Siberia to Calcutta in India on foot. Tesson concluded the journey was plausible, though there are inconsistencies, such as Rawicz"s claim of ten days without water in the Gobi.
Tesson wrote a book with photographer Thomas Goisque based on this experience, Sous l"étoile de la liberté.
Six mille kilomètres à travers l"Eurasie sauvage ("Under the star of liberty Six thousand kilometers across the Eurasian wild")
In 2010, Tesson undertook a project to live alone for six months on the shores of Lake Baikal in a rustic cabin during winter, about 500 km south of Irkutsk. In his own words, "the recipe for happiness: a window on Baikal, a table by the window." He recounted his time in Siberia in a book, The Consolations of the Forest: Alone in a Cabin on the Siberian Taiga.
He also released a film titled Alone, 180 days on Lake Baikal (2011), directed by Tesson and Florence Tran.