An opening bowler and useful batsman in the lower order, Dayle Hadlee was selected to tour England, India and Pakistan in 1969 after only three first-class matches, none of them in the Plunket Shield. He played in two Tests in England, taking six wickets. He played all six Tests against India and Pakistan, taking 21 wickets at 15.95, including his best Test figures of 4 for 30 in Hyderabad, and making 152 runs at 16.88, including his only Test fifty, 56 at Karachi, when he had a partnership of 100 in 90 minutes for the eighth wicket with Bryan Yuile.

He was hampered by injury for a couple of years and didn't make his Plunket Shield debut for Canterbury until 1971-72. In 1972-73 he took 32 wickets in the Shield at 13.50, opening the bowling with his brother Richard, who took 28 at 15.64. Dayle took 6 for 42 against Otago, and 4 for 28 and 7 for 88 against Northern Districts. Richard made his Test debut in the First Test against Pakistan, then lost his place to Dayle for the last two Tests of the series. Neither brother made much impact. Between the Second and Third Tests New Zealand played its first One Day International, beating Pakistan by 22 runs in fading light in Christchurch; Dayle took 4 for 34.

Dayle and Richard each took 38 first-class wickets on the tour of England in 1973. Dayle played all three Tests, taking 10 wickets at 34.00, including 4 for 42 in the first innings of the First Test. That match, the first Test in which the brothers had played together, was Richard's only Test of the series.

Dayle toured Australia in 1973-74, playing all three Tests, and then played all three when Australia toured New Zealand later that summer, taking 16 wickets in the six matches. In the Second Test in Christchurch, he took 1 for 42 and 4 for 75 in New Zealand's first Test victory over Australia. He played both Tests against the touring English side in 1974-75.

At the 1975 World Cup he took seven economical wickets in the three qualifying matches but was severely punished by Alvin Kallicharran in the semi-final against West Indies. He played all three Tests against the Indian touring team in 1975-76, taking three wickets in New Zealand's victory in Wellington, when Richard took 11. Dayle's final Test was New Zealand's first ever Test victory over England, in Wellington in 1977-78, in which he took no wickets while Richard took 10.^[8]

He had taken his best first-class innings figures of 7 for 55 for Canterbury against Wellington earlier in the 1977-78 season.^[9] His only first-class century came in 1982-83, when he scored 109 not out in Canterbury's victory over the touring Sri Lankans.^[10] He retired after the 1983-84 season, in which he took 17 wickets at 16.88.^[11]

After he retired he took up coaching. In 1999 he described the English cricketer Ian Bell as "the best 16-year-old I've ever seen".^[12] In 2008 he was appointed to coach at the Global Cricket Academy in Dubai.^[13]