McCullum, 33, was crowned at the New Zealand Cricket Awards held in a glitzy ceremony at Auckland's Langham hotel tonight.
He led New Zealand to the World Cup final in Melbourne last week and although they fell one game short of perfection, his attacking and instinctive captaincy captured the imagination of the public who embraced this team like never before.
Lost in the World Cup hubbub, perhaps, was the fact that McCullum had a brilliant year with the bat, becoming the first New Zealander to score 1000 test runs in a calendar year.
He backed up his 302 against India in Wellington last season with a brilliant double century against Pakistan, which helped his team to a series draw, and a blazing 195 against the touring Sri Lankans to christen Hagley Oval as a test opener.
McCullum was also named Herald New Zealander of the Year in 2014, in part for his cricket exploits, but also for taking a stand against corruption in the game. He is set to testify at Chris Cairns' perjury trial at London's High Court in October.
Under McCullum's leadership, the Black Caps recorded their most successful test season, claiming five test wins.
He scored an ODI century against Sri Lanka in the lead up the ICC Cricket World Cup and was selected as the captain of the ICC tournament team for his aggressive batting and captaincy.
McCullum won the supreme award ahead of Kane Williamson, who claimed the Redpath Cup for first-class batting, and Trent Boult, who was the winner of the Winsor Cup for bowling.
It is the first time the Sir Richard Hadlee Medal has not been a recipient of either of the other two major awards.
Williamson had a season to savour in 2014-15 and was recognised in winning the Twenty20 International Player of the Year, the ODI Player of the Year and the Test Player of the Year.
He scored three test centuries and the highest score of his test career; a remarkable 241 not out against Sri Lanka at the Basin Reserve. He was one of three New Zealanders included in the ICC test team of the year.
He also scored three ODI centuries including one as captain in the United Arab Emirates, to see the Black Caps home for a series win over Pakistan.
Well known for his exploits with the red ball, Boult became the New Zealand record holder for the most wickets taken at a World Cup with 22 scalps. This surpassed Geoff Allott's record of 20 wickets in 1999.
Earlier in the year, he brought up his 100th test wicket.
White Ferns captain Suzie Bates has been named as the International Women's Player of the Year after her stellar season on the international stage.
Special tributes were also made tonight to the three Black Caps - Daniel Vettori, Kyle Mills and Jamie How - who recently announced their retirements from the international game.
New Zealand Cricket Awards 2014-15 season
Sir Richard Hadlee Medal: Brendon McCullum
International Women's Player of the Year: Suzie Bates
Redpath Cup (Batting): Kane Williamson
Winsor Cup (Bowling): Trent Boult
ANZ Twenty20 International Player of the Year: Kane Williamson
ANZ ODI International Player of the Year: Kane Williamson
ANZ Test Player of the Year: Kane Williamson
Domestic Cricketer of the Year: Men: Andrew Ellis (collected by Lee Germon)
Domestic Cricketer of the Year: Women: Amy Satterthwaite
Bert Sutcliffe Award: Ross Dykes
