Camier began racing grasstrack at age six and won five British championships in that discipline before moving to road racing. He won the British Junior 80cc Road Racing title in 1998 and the British 125cc title in 2001. In 2005 he claimed the British Supersport crown, building a working relationship with Honda that included an unusually early appearance at the Suzuka 8 Hours that same year at just eighteen years old.
Camier made his British Superbike Championship debut in 2007 with Bike Animal Honda, reaching the podium in his first three races before a crash at Silverstone and an end-of-season accident at Cadwell Park — which broke his left femur and right pelvis — disrupted his progress.
In 2008 he joined the GSE Racing Airwaves Ducati team alongside former champion Shane Byrne and finished fifth overall, taking his first three BSB victories.
For 2009, GSE switched to Yamaha and Camier delivered the most dominant British Superbike Championship season in recent memory, winning 18 races — a record — and clinching the title with four rounds remaining by overtaking his nearest rival James Ellison on the penultimate lap of race one at Silverstone. His dominance was such that the BSB organisers subsequently introduced the Showdown format for 2010 to address the potential for early title clinches of this kind.
Camier's BSB title earned an immediate call-up to the Superbike World Championship. He joined the Aprilia squad for the final two rounds of 2009, replacing the injured Shinya Nakano. At Portimao in his second meeting he finished sixth and seventh.
He raced full-time with Aprilia in 2010. At Miller Motorsport Park he finished second to teammate Max Biaggi in race two, contributing to Aprilia's first 1–2 in the series. From 2015 he competed for MV Agusta Reparto Corse on an MV Agusta F4, representing the Italian brand during a period of effort to re-establish their WorldSBK presence.
In late 2017, Camier signed to ride for Ten Kate Racing Honda in 2018 on a Honda Fireblade SP2 alongside Jake Gagne. He continued with Honda into 2019 with a fully factory-backed team alongside Ryuichi Kiyonari. Shoulder injuries increasingly affected his availability and performance across the Honda years, and for the 2020 season he was contracted to Barni Ducati but was unable to start the campaign due to continuing shoulder problems, leading to a mutual parting.
After his riding career ended due to injury, Camier moved into team management. For the 2021 season he was announced as team manager of the Honda World Superbike team under Honda Racing Corporation. He also became a rider-coach for Sam Lowes at the Elf Marc VDS Racing team in Moto2, with that team also establishing a new WorldSBK entry using a Ducati Panigale 955.
Camier's 2009 British Superbike Championship campaign — 18 wins, title clinched with four rounds in hand — stands as one of the most statistically dominant seasons in BSB history and remains his signature achievement. His decade-long WorldSBK career spanned Aprilia, MV Agusta, and Honda, representing manufacturer diversity unusual for the period. His later career as team manager and rider-coach demonstrates a continued connection to the sport's upper echelons after competitive riding became impossible.