Early career Born in
Letterkenny,
County Donegal, Deignan first competed on a bike in 1997 during the annual Sligo to Letterkenny charity cycle. He attended
St Eunan's College for his secondary education. Before turning professional in 2005, he rode for amateur club where he performed well. In the
Baby Giro of 2004 after recovering from an earlier crash, he performed well on the mountainous stages. He won the final stage and the general classification of the 2004 Ronde de l'Isard as an amateur. His first professional road race win was in the
Tour du Doubs when he attacked a breakaway group that contained his fellow Irishman and teammate at the time
Mark Scanlon. Other notable performances were ninth place in the
UCI World Championships Under 23 road race, fifth place in European championship under 23 road race, and second place on a mountainous stage of the 2006
Tour de l'Avenir stage race. After an injury-plagued early season, Deignan entered and finished his first grand tour with the
2007 Vuelta a España, where he finished prominently with 10th, 12th and 16th in several mountain stages. He qualified to represent Ireland at the
2008 Beijing Olympics. He finished in 81st place (15 minutes and 53 seconds behind winner
Samuel Sánchez and five minutes behind team mate
Nicolas Roche) in the road race on 9 August. Deignan along with Roche and Roger Aiken made up the Irish team for the
2008 World Championships in Varese on 28 September. None of the three finished the demanding race.
Cervélo TestTeam (2009–2010) For the 2009 season Deignan rode with the . He raced the
Giro d'Italia, achieving a top ten finish in one stage and featuring prominently in others, with his team winning 4 stages in total. On 17 September 2009 he achieved his first grand tour stage victory, in stage 18 of the
Vuelta a España into Avila, after a 2-man battle with the Czech
Roman Kreuziger of . By finishing 10 minutes clear of the peloton he climbed to 9th in the general classification. He became the first Irishman to win a stage on a Grand Tour since
Stephen Roche's last-stage success at the
Tour de France in
1992. Deignan was selected to ride for Ireland in the 2009 World Elite Road Race Championship in Mendrisio, Switzerland (23–27 September) alongside Nicolas Roche and
Dan Martin. After his Vuelta performance, Deignan reached a personal high 2009 world ranking of 71st. Deignan was the best Irish finisher when placing 40th at the
2009 UCI Road World Championships – Men's road race in Mendrisio. He ended the 2009 season UCI ranked 75th, with 61 points, which helped Ireland to 16th in the team rankings.
RadioShack (2011) It was announced after illness ruined his 2010 season, Deignan signed for for 2011.
United Healthcare (2012–2013) After one season with RadioShack, he signed on with for the 2012 season. He rode the
Giro d'Italia which began in Belfast and travelled to Dublin in the opening stages. Deignan led Sky at the
Tour de Pologne, finishing seventh overall. He also rode the
Vuelta a España, where he helped
Chris Froome to second overall. In November 2018, Deignan announced his retirement from professional cycling. ==Personal life==