Boult is a left-arm fast medium swing bowler. He makes up for his relative lack of height with deceptive pace and the ability to swing the ball both ways. Boult's primary weapon is the inswinger to the right-hander. Perhaps unsurprisingly, his childhood cricketing hero was Wasim Akram. In 2013, in a radio interview, former New Zealand captain Jeremy Coney rated Boult as New Zealand's best bowling discovery since Shane Bond. He is also known to haul in one-handed catches with either hand, both in Basin Reserve. In 2014, he became the 4th test bowler since Richard Hadlee, Chris Martin and Iain O'Brien to claim 30+ wickets in consecutive years. He has developed a good opening bowling partnership with Tim Southee, having taken 46% of all wickets between them since 2013, especially since the retirement of Martin. In Tests, they are ably complemented by Neil Wagner's short left-arm seam deliveries. In August 2019, in the series against Sri Lanka, Boult became the third bowler for New Zealand to take 250 wickets in Test cricket.
Boult is a useful right-handed tailender, having scored a half century against Bangladesh in a 2013 test. He tends to open his stance by stepping the left (front) foot off to the side for his back-foot cover drive, much akin to Shivnarine Chanderpaul, or turns sideways and leans his whole body back over leg stump and play the bat across to play his cut shots.