Brathwaite was a student at Combermere School in Saint Michael, Barbados. Brathwaite had scored 28 centuries in local cricket in Barbados before being included in West Indian under-15 team competing in the Clico International Under-15 Cricket Championships in 2008. He made his first-class cricket debut for Combined Campuses and Colleges against his home country Barbados on 3 April 2009 where he made 73 runs opening the batting. Later that month, he was selected for the Barbados team to play Guyana at Providence Stadium.

In August 2012, Brathwaite led West Indies under-19 team in the Under-19 World Cup in Australia. In September 2013, Brathwaite toured with West Indies A to India for an unofficial test series he finished with a total of 334 in 6 innings with an average of 55.66. This included two half-centuries and a hundred. In January 2014 Brathwaite was announced as Barbados' Regional 4-day captain. Brathwaite was part of the Barbados Regional super 50 2014 squad which won the competition and had scores of 2,29*,55* and 36 against Trinidad, Leeward Islands,Guyana and Trinidad respectively. Brathwaite started off the first-class season as captain well, taking Barbados to the top of the table. Barbados has played 5 matches which Brathwaite made 85 and 15 against Winward Island,19 and 5 against Guyana,91 vs Combined Campuses and Colleges(CCC),0 against Trinidad and 21 and 91 against Jamaica.

In June 2009, Brathwaite was called into the West Indian squad for the series of Test matches against Bangladesh as a replacement for players participating in a strike called by the West Indies Players' Association.

In November 2013 Brathwaite got a test recall for West Indies' test match series against New Zealand in December replacing an injured Chris Gayle after attempting a run a in the second One-Day International against India. Brathwaite is also a member of Sagicor High Performance Centre in Barbados. Before Brathwaite reached New Zealand he went through some trouble getting the necessary visa to fly to New Zealand: he had to wait 2 weeks before he was able to fly. On Brathwaite's return to the West Indies he scored 45 and 7.

His best bowling figure in a test innings is 6/29 which came against Sri Lanka at P Sara Oval, Colombo in 2015. In December 2015, at the Blundstone Arena in Hobart in the 2nd innings of the 1st test of the Sir Frank Worrell Trophy series against Australia, Brathwaite was last man out for a belligerent 94. His 94 accounted for 63.51% of the West Indies total of 148, the 4th highest percentage of runs in a completed innings in Test Match history.

He made his One Day International (ODI) debut for the West Indies against Pakistan on 30 September 2016.

On 1 November 2016, Brathwaite carried his bat in the first innings becoming the fifth player for the West Indies to do so by scoring 142 not out against Pakistan at the Sharjah Cricket Stadium. In the second innings, he became the first opener to remain unbeaten in both innings of a Test.^{[6] [7] [8]}.

Test captaincy

In November 2017, he was named Test captain for 2nd Test against New Zealand, replacing Jason Holder who was suspended for one match,^[9][10] becoming the 37th Test captain of West Indies.^[11]