# Swimming at the 2019 World Aquatics Championships – Men's 100 metre backstroke

The Men's 100 metre backstroke competition at the 2019 World Championships was held on 22 and 23 July 2019. The defending champion was Xu Jiayu, and he successfully defended his title. Jiayu set a competition record in the semifinals by winning his semifinal in 52.17 seconds.

## Records

Prior to the competition, the existing world and championship records were as follows.
| World record | Ryan Murphy (USA) | 51.85 | Rio de Janeiro, Brazil | 13 August 2016 |
| Competition record | Aaron Peirsol (USA) | 52.19 | Rome, Italy | 2 August 2009 |
The following new records were set during this competition.
| Date | Event | Name | Nationality | Time | Record |
| 22 July | Semifinal | Xu Jiayu | China | 52.17 | CR |

## Results
### Heats

The heats were held on 22 July at 10:20.
Due to backstroke wedge malfunctions, Simone Sabbioni and Dylan Carter swam alone in new series, after the end of the normal series, and both achieved classification. The swimmers who had obtained the vacancy, and would be disqualified after these 2 series (Thomas Ceccon and Richárd Bohus), received extra vacancies for the semifinal, that ended up being with 18 swimmers.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 6 | 4 | Xu Jiayu | China | 52.85 | Q |
| 2 | 5 | 2 | Guilherme Guido | Brazil | 52.95 | Q, SA |
| 3 | 5 | 4 | Mitch Larkin | Australia | 53.12 | Q |
| 4 | 5 | 5 | Matt Grevers | United States | 53.22 | Q |
| 5 | 6 | 5 | Ryosuke Irie | Japan | 53.38 | Q |
| 6 | 7 | 3 | Evgeny Rylov | Russia | 53.45 | Q |
| 7 | 6 | 3 | Robert Glință | Romania | 53.64 | Q |
| 8 | 6 | 6 | Daniel Martin | Romania | 53.65 | Q |
| 9 | 7 | 4 | Ryan Murphy | United States | 53.69 | Q |
| 10 | 5 | 3 | Markus Thormeyer | Canada | 53.77 | Q |
| 11 | 6 | 0 | Mikita Tsmyh | Belarus | 53.81 | Q, NR |
| 12 | 7 | 2 | Apostolos Christou | Greece | 53.82 | Q |
| 13 | 8 | 5 | Simone Sabbioni | Italy | 53.85 | Q |
| 14 | 7 | 5 | Kliment Kolesnikov | Russia | 53.89 | Q |
| 15 | 5 | 7 | Luke Greenbank | Great Britain | 53.95 | Q |
| 16 | 9 | 8 | Dylan Carter | Trinidad and Tobago | 54.03 | Q, NR |
| 17 | 5 | 6 | Thomas Ceccon | Italy | 54.04 | Q |
| 18 | 6 | 8 | Richárd Bohus | Hungary | 54.07 | Q |
| 19 | 7 | 1 | Christopher Reid | South Africa | 54.12 | |
| 20 | 7 | 0 | Tomáš Franta | Czech Republic | 54.16 | NR |
| 21 | 6 | 2 | Shane Ryan | Ireland | 54.24 | |
| 22 | 5 | 1 | Li Guangyuan | China | 54.29 | |
| 22 | 7 | 8 | Yakov Toumarkin | Israel | 54.29 | |
| 24 | 7 | 7 | Bradley Woodward | Australia | 54.41 | |
| 25 | 5 | 0 | Lee Ju-ho | South Korea | 54.56 | |
| 26 | 6 | 1 | Christian Diener | Germany | 54.68 | |
| 27 | 7 | 9 | Radosław Kawęcki | Poland | 54.76 | |
| 28 | 4 | 4 | Roman Mityukov | Switzerland | 54.87 | |
| 29 | 6 | 7 | Bernhard Reitshammer | Austria | 54.94 | |
| 30 | 6 | 9 | Bradlee Ashby | New Zealand | 55.02 | |
| 31 | 4 | 2 | Gabriel Lópes | Portugal | 55.33 | |
| 32 | 3 | 7 | Merdan Ataýew | Turkmenistan | 55.34 | |
| 33 | 4 | 1 | Metin Aydin | Turkey | 55.40 | |
| 34 | 4 | 3 | Tomoe Zenimoto Hvas | Norway | 55.42 | |
| 35 | 4 | 6 | Anton Loncar | Croatia | 55.44 | |
| 36 | 4 | 0 | Srihari Nataraj | India | 55.55 | |
| 37 | 5 | 9 | Hugo González | Spain | 55.67 | |
| 38 | 3 | 5 | Karl Johann Luht | Estonia | 55.75 | |
| 39 | 4 | 9 | Mohamed Samy | Egypt | 55.87 | |
| 40 | 3 | 4 | Adil Kaskabay | Kazakhstan | 55.89 | |
| 41 | 4 | 7 | Chuang Mu-lun | Chinese Taipei | 56.01 | |
| 42 | 3 | 6 | Jack Kirby | Barbados | 56.25 | |
| 43 | 3 | 3 | Ģirts Feldbergs | Latvia | 56.34 | |
| 44 | 4 | 5 | Omar Pinzón | Colombia | 56.37 | |
| 45 | 3 | 1 | Jason Arthur | Ghana | 56.86 | |
| 46 | 3 | 8 | Kristinn Þórarinsson | Iceland | 56.99 | |
| 47 | 4 | 8 | Armando Barrera | Cuba | 57.00 | |
| 48 | 3 | 0 | Tern Tern Jian Han | Malaysia | 57.34 | |
| 49 | 2 | 4 | Filippos Iakovidis | Cyprus | 58.26 | |
| 50 | 2 | 6 | Gabriel Castillo | Bolivia | 58.47 | |
| 51 | 2 | 9 | Ali Al-Zamil | Kuwait | 58.63 | |
| 52 | 3 | 2 | Robinson Molina | Venezuela | 59.08 | |
| 53 | 2 | 3 | Kasipat Chograthin | Thailand | 59.10 | |
| 54 | 2 | 5 | Dimuth Peiris | Sri Lanka | 59.62 | |
| 55 | 2 | 2 | Syed Tariq | Pakistan | 59.71 | |
| 56 | 2 | 8 | Netani Ross | Fiji | 1:00.30 | |
| 57 | 2 | 7 | Eisner Barberena | Nicaragua | 1:00.56 | |
| 58 | 1 | 3 | Heriniavo Rasolonjatovo | Madagascar | 1:00.87 | |
| 59 | 2 | 1 | Ado Gargović | Montenegro | 1:01.37 | |
| 60 | 1 | 5 | Omar Al-Rowaila | Bahrain | 1:02.96 | |
| 61 | 2 | 0 | Juhn Tenorio | Northern Mariana Islands | 1:04.91 | |
| 62 | 1 | 4 | Juwel Ahmmed | Bangladesh | 1:05.00 | |
| 63 | 1 | 6 | Hedayatullah Noorzad | Afghanistan | 1:31.35 | |
| | 3 | 9 | Driss Lahrichi | Morocco | DNS | DNS |

### Semifinals

The semifinals were held on 22 July at 20:18.

#### Semifinal 1

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 3 | Evgeny Rylov | Russia | 52.44 | Q, NR |
| 2 | 5 | Matt Grevers | United States | 52.82 | Q |
| 3 | 4 | Guilherme Guido | Brazil | 53.23 | Q |
| 4 | 1 | Kliment Kolesnikov | Russia | 53.44 | |
| 5 | 7 | Apostolos Christou | Greece | 53.56 | |
| 6 | 2 | Markus Thormeyer | Canada | 53.59 | |
| 7 | 6 | Daniel Martin | Romania | 53.71 | |
| 8 | 0 | Richárd Bohus | Hungary | 53.94 | |
| 9 | 8 | Dylan Carter | Trinidad and Tobago | 54.08 | |

#### Semifinal 2

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Xu Jiayu | China | 52.17 | Q, CR |
| 2 | 2 | Ryan Murphy | United States | 52.44 | Q |
| 3 | 5 | Mitch Larkin | Australia | 52.91 | Q |
| 4 | 3 | Ryosuke Irie | Japan | 53.13 | Q |
| 5 | 6 | Robert Glință | Romania | 53.40 | Q |
| 6 | 1 | Simone Sabbioni | Italy | 53.71 | |
| 7 | 8 | Luke Greenbank | Great Britain | 53.75 | |
| 8 | 0 | Thomas Ceccon | Italy | 54.20 | |
| 9 | 7 | Mikita Tsmyh | Belarus | 54.24 | |

### Final

The final was held on 23 July at 21:06.
| Rank | Lane | Name | Nationality | Time |
| | 4 | Xu Jiayu | China | 52.43 |
| | 5 | Evgeny Rylov | Russia | 52.67 |
| | 2 | Mitch Larkin | Australia | 52.77 |
| 4 | 3 | Ryan Murphy | United States | 52.78 |
| 5 | 6 | Matt Grevers | United States | 52.82 |
| 6 | 7 | Ryosuke Irie | Japan | 53.22 |
| 7 | 1 | Guilherme Guido | Brazil | 53.26 |
| 8 | 8 | Robert Glință | Romania | 54.22 |