But Josh Murray, a former Labor staffer, rejected any suggestion that he was part of a "conspiracy" to take on the lucrative job having taken a pay cut from his "highly rewarding" private-sector position for the public role.
The appointment of the former engineering and construction executive to the $588,250-a-year job has been criticised after it was revealed that recruiters initially dismissed him as lacking the necessary experience.
Mr Murray used a parliamentary inquiry into his appointment on Thursday to take aim at the same recruiters.
They wrongly called him "Josh Gordon", appeared to think he was applying for an anti-corruption role and were slow to pass on relevant material to the government, he said.
"They made very short judgments based on job descriptions instead of discussions," Mr Murray said.
Describing his political history as "writ-clear" on his CV, the former staffer to Labor premier Morris Iemma confirmed he remained a party member until June.
But denied ever being "active" in a branch.
As well as dropping $500 into Transport Minister Jo Haylen's election kitty to attend a fundraiser dinner headlined by the prime minister, Mr Murray said he attended two other pre-election Labor fundraisers "while a private citizen".
His wife paid $250 a head for a former premiers' dinner at parliament and $100 a seat for a trivia night for the premier's Kogarah branch.
The trivia night was partly organised in tribute to Mr Murray's father-in-law, a former Labor transport minister.
Mr Murray added he had known Premier Chris Minns since their days as political staffers and he considered the Labor leader a friend.
But they never discussed his application for the transport secretary role, he said.
Mr Murray did not tell the recruiters about his political donations, which fell below the state's declarable threshold of an annual $1000 per person.
"Those matters were not material," he said.
Mr Murray added he understood his Labor links would dominate the headlines, but he underlined his 15 years at Laing O'Rourke and his motivation and passion to serve NSW.
"I made a tough career call based on the opportunity to make a difference," he said.
"I was asked to apply again tomorrow, knowing what I know now, I would still say yes."
Ms Haylen shirked the inquiry's invitation to appear, instead facing a barrage of questions on Thursday from the press.
She trumpeted the skills, experience and intelligence of her new secretary and said reasonable people would think it was "ridiculous" that small donations could influence her decision to appoint Mr Murray to such a critical role.
Ms Haylen denied wasting the time of senior public servant and former international transport executive Benedicte Colin, who recruiters ranked as a better prospect for the role than Mr Murray.
Both applicants were put forward to Ms Haylen by an assessment panel, leading the minister to select the Laing O'Rourke executive.
Mr Murray started two weeks ago. He cannot participate in matters concerning his former employer - a major government contractor - until August 2024.
