28 Millimetres: Women Are Heroes, School in Bo City, Sierra Leone

28 Millimetres: Women Are Heroes, School in Bo City, Sierra Leone 2008

124 cm x 186 cm
Cibachrome print mounted on aluminium under perspex

Dubbed "the hippest street artist since Banksy" by The Times, JR describes himself as a "photograffeur", using photography as his medium and graffiti as his method. Nonetheless, he has described himself as "neither a photographer, nor a street artist", and admittedly even both labels combined undersell the ambitious nature of his work – plus its phenomenal reach.

His giant monochrome outdoor portraits of local people adorn some of the world's least desirable neighbourhoods. JR's gallery works are meticulously composed – dramatic and often exotic photographs of these giant pasted portraits in turn. The work celebrates the timeless indomitability of the human spirit, and a rapidly accelerating pan-national culture. The initial portraits are also usually taken by himself, printed digitally in black and white and posted using wheatpaste. These ambitious projects are entirely self-funded: "You wouldn't take it the same way if I did it with L'Oreal", he told The Observer newspaper in 2010.

JR's purpose is succinct: to establish empathy with sectors of the population who often find themselves stereotyped or demonised by global public perception. The perfect example is a piece known as The Holy Triptych – it features a rabbi, a priest and an imam pulling funny faces for JR's camera. JR reminds us that compassion, warmth and humour are constants, glimmers of which still remain even under the most horrific circumstances.

The work also serves to undermine materialism and the aggressive form of selfishness that scarcity often generates. As Damien Thompson posits in his 2013 examination of consumer culture The Fix, "we have become more interested in things than people". JR's work goes some way towards reminding us that our fellow man is of the utmost import to our own existence.

A typical teenage tagger, JR's own legend has it that he found a camera while out on the graffiti trail in the Paris Metro. His first of many impeccably produced projects took place close to home. Beginning in 2004, Portrait of a Generation took as its subject the listless youth of Paris's infamous banlieues, the out-lying suburbs immortalised in the film La Haine, where social engineering has driven the impoverished immigrant population to the fringes of both the city and Gallic society itself. One of JR's most enduring images, Ladj Ly, featuring the subject raising a video camera as if he were aiming a firearm, was part of this body of work. An enormous version of Ladj Ly was draped over the exterior of London's Tate Modern museum in 2008 and the photograph adorns the front cover of Lazarides' book of emerging art from 2009, Outsiders: Art by People. Lazarides was by now exhibiting JR's work extensively, including at what is now The Outsiders London in 2008, at Outsiders New York in 2009, Grifters at Lazarides Rathbone in 2010 and in the Eurotrash group exhibition, Los Angeles, the same year.

JR's international work corresponded with an explosion of street art coverage on the Internet. Illegal or "uncommissioned" works, that would previously have lasted sometimes only minutes, were immortalised on the world wide web. After Portraits of a Generation in 2007, JR travelled to Palestine, inviting Israeli settlers to pose face-to-face with their Palestinian counterparts in similar jobs. Dubbed Face2Face, the pictures were displayed on both sides of the West Bank Barrier wall. His next project 2008's Women are Heroes involved portraits of locals in the lawless favella Morro da Providencia, many of whom were the mothers, sisters and daughters of men caught up in the ongoing crime wars that dominate life in the Rio di Janeiro slums. The landmark work Tree of Providencia was created during this dangerous exercise (journalists are banned, and Non-Governmental Organisations do not work in Morro di Providencia). Women are Heroes also incorporated a delegation to Kiberia in Kenya, where JR covered 2000 square metres of corrugated rooftops with images of impoverished and often starving female refugees. The initiative has also travelled to Liberia, India, Sierra Leone, and Cambodia. Portraits of a Generation, Face2Face and Women are Heroes are collected together in the book 28 Millimetres, with a specific additional volume collecting the Women are Heroes photographs.

Wrinkles of the City was JR's next major project. In 2008 his portraits of seniors were displayed in Cartagena, Spain. The initiative showed an evolution in how JR displayed his work, incorporating the weathered architecture of Cartegena within his final public compositions. Artistically, Wrinkles of the City served as a reminder of the symbiotic relationship between people and places, in an era of isolated lifestyles within environments teeming with our fellow man. Wrinkles of the City has extended to Los Angeles, Shanghai and Havana, where the images on display were further embellished by the work of famed Cuban-American street artist Jose Parla.

The Unframed project saw JR use archive photography in startling public contexts. For example, in 2009 a photograph from the Chernobyl nuclear disaster was displayed in Grottaglie in Italy to highlight the Mafia's illegal dumping of toxic waste in the area. The city of Vevey in Switzerland was plastered with photographs from Lausanne's Musee d'Elysee, presenting historical imagery in a poignant and sometimes contrasting light.

In 2011 JR was awarded the TED Prize which donates one million dollars "to give one extraordinary individual a chance to think bigger." The artist conceived Inside Out, "the world's largest global art project", inviting people the planet over to donate their own photographs and have them displayed in JR's signature style. "This is a collaboration between the artist, JR, and you" read the universal invitation. Neighbourhoods in 208 different countries are now festooned with images of more than 150,000 people in total. A documentary giving a small insight into the strength of will needed to realise such a goal was shown on US premium cable channel HBO in May 2013.