He also improved his 400 m personal best by 0.7 seconds with 45.27 s. Richards made his outdoor World Championship debut at London 2017.

Competing in the 200 m, he ran the fastest time in the heats of 20.05 s, and the next day he won his semi-final in 20.14 s. He then went on to win the bronze medal in the final; Ramil Guliyev of Turkey won gold in 20.09 s, while Wayde Van Niekerk of South Africa beat Richards to the silver medal by exactly 1/1000 of a second, clocking 20.106 to 20.107 s.[5] Richards stated that his race had been undermined when he slipped coming out of his blocks.

"[6] Three days later, he ran the second leg for Trinidad and Tobago in the men's 4 x 400 m relay, making considerable ground off the USA's Gil Roberts before handing the baton to Machel Cedenio.

In March 2018, he competed in the World Indoor Championships in Birmingham, as the second leg of Trinidad and Tobago's 4 x 400 m relay.

"[13] Richards qualified for the delayed 2020 Summer Olympics held in Tokyo in the men’s 200-metre event, and clocked a season’s best time of 20.10 s while finishing in third place in his semi-final to advance to the final.

[22] At the Birmingham Commonwealth Games in United Kingdom, Richards won the 200 m title for the second time beating England's Zharnel Hughes.

[25] In July 2023, Richards won the 400 m at the CAC Games in San Salvador in a new personal best of 44.54 s.[26] He went on to win another gold as part of the men's 4x400 m relay.

[29] At the 2024 Paris Olympics, Richards finished fourth in the 400 m in a national record of 43.78 s, finishing behind bronze-medallist Muzala Samukonga by just 0.04 s.[30] His time surpassed Machel Cedenio's previous national record of 44.01 s, meaning Richards was the first Trinidadian to run a sub-44 400 m.[31] In October 2024, it was announced that he had signed up for the inaugural season of the Michael Johnson founded Grand Slam Track.

As of 19 September 2024, Richards holds the track record for 400 metres for San Salvador where on 6 July 2023 he set a time of 44.54 seconds.