In 2009, Child significantly improved her personal best for the 400 m hurdles from 56.84 to 55.32, to finish second at the European U23 Championships in Kaunas, Lithuania, behind fellow British athlete
Perri Shakes-Drayton. She also qualified for that year's
World Championships in Berlin, reaching the semi-finals. In 2010, she further improved to 55.16 at the London Diamond League in August. Then in October, she won a silver medal at the
Commonwealth Games in Delhi in 55.62. In 2012, Child ran below 55 seconds for the 400 metres hurdles for the first time, with 54.96 on 2 June in Geneva. Two weeks later, she earned Olympic selection, with 55.53 for second behind Shakes-Drayton at the Olympic trials. At the
London Olympics, she reached the semi-finals, running 56.02. She won two medals at the
2013 European Indoor Championships in Gothenburg, with silver in the 400 metres behind teammate Perri Shakes-Drayton, breaking the Scottish indoor record in the process, with 51.45. She then added a gold in the 4 × 400 m relay. The British quartet of
Christine Ohuruogu,
Shana Cox, Child, and Shakes-Drayton also improved the UK indoor record to 3:27.56. Outdoors, she broke the Scottish 400 metres hurdles record with 54.22 in Birmingham in June. Then in August, at the
World Championships in Moscow, she ran 54.32 in her semi-final to reach the final. In the final she was fifth in 54.86. Alongside Cox,
Margaret Adeoye and Ohuruogu, she won a bronze medal in the 4 × 400 metres relay. Child captained the first ever Scotland team at the
Glasgow International match in January 2014. As captain of the GB & NI team at the
2014 World Indoor Championships in Sopot, she won a bronze medal in the 4 × 400 metres relay. 2014 also saw her secure her first 400 metres hurdles British title, and take victory at the first ever
IAAF Diamond League meeting in Scotland, the
Glasgow Grand Prix. in a European leading time of 54.39. At the
2014 Commonwealth Games, Child captained the Scottish athletics team to its best medal haul since
1990, winning another silver medal in the 400 m hurdles behind
Kaliese Spencer of Jamaica. Two weeks later, at the
European Championships in Zurich, she won a gold medal in the 400 m hurdles, running 54.48. She became the first British woman to win the European 400 m hurdles title for 20 years, the previous British winner being
Sally Gunnell in 1994. In May 2016, Child won the 400 metres hurdles at the
Doha Diamond League meeting in a time of 54.53 seconds, competing for the first time under her married name, Doyle. On 15 July 2016, she won the Diamond League meeting in Monaco, setting a new personal best of 54.09 seconds. At the
Rio Olympics, she reached the final of the
400 metres hurdles, finishing eighth in 54.61, before going on to win a bronze medal in the
4 × 400 metres relay, the first Scottish Olympic track and field medal since
1988. In July 2017, it was announced that Doyle had been elected by her team-mates as Captain for the GB Team at the
World Championships in London, which included the largest number of Scottish athletes ever selected for a major championships. At the Championships she finished 8th in the final of the
400 m hurdles but would go on to win a silver in the
4 × 400 m relay. In winning the silver medal, Doyle surpassed
Yvonne Murray as the most decorated Scottish athlete in Olympic World, European and Commonwealth competition. In 2018, Doyle started the season well winning a bronze medal at the
World Indoor Championships in
Birmingham in a seasons best time, despite tearing her calf in the final. Along with
Laura Muir, they were the first Scottish individual medalists at the championships for 25 years. Chosen by her peers to be the first ever female flag bearer for
Scotland (chosen for the
opening ceremony) at the
Commonwealth Games, she went on to win her third Commonwealth Games silver medal with a time of 54.80 seconds. In August, Doyle made a joint-British record equalling fifth appearance at the
European Championships in
Berlin In
2019, Doyle was included in the largest contingent of Scottish athletes to be selected for a British team at a
European Indoor Championships for over 50 years.
Retirement In August 2019, Doyle announced that she would miss the rest of the season as she was due to have a baby in January 2020, although she planned to return to athletics after the birth. Doyle announced her retirement in May 2021. Doyle retired as the most decorated
Scottish track and field athlete of all time. She accumulated a total of 17 medals from major championships at
Olympic,
world,
European, and
Commonwealth level. If the
World Relays and
Continental Cup are to be included the medal tally totals 19. ==Personal life==