A chicken farmer and axeman, Mr Kerin gained arts and economics degrees as an external and part-time student and became a research economist with what's now the Australian Bureau of Agriculture and Resource Economics and Sciences.
Mr Kerin joined the Labor party largely because he opposed the Vietnam war.
He won the federal seat of Macarthur in the 1972 election but lost it in the 1975 Malcolm Fraser-led Liberal landslide.
He went back to ABARES, despite the opposition of some senior public officials, however the minister, the Nationals’ Ian Sinclair, ruled he should be re-employed.
When Gough Whitlam left parliament after his 1977 defeat, Mr Kerin took over his seat of Werriwa.
In 1980, Mr Kerin went to the front bench as primary industries spokesman and kept the portfolio when Bob Hawke came to power in 1983. He became minister for primary industries and energy in 1987.
Mr Kerin’s broad approach during his seven years running farm policy was to shift the emphasis to marketing, to boost research and to reform the myriad statutory marketing authorities.
He started with the Australian Meat and Livestock Corporation, imposing selection procedures to ensure a broader expertise on its board, splitting research off to a separate board and generally requiring the organisation to act more commercially and transparently.
That became the model for other authorities.
Dairy was his most fiery issue as he tried to reform the highly protected and restricted industry, in which Victoria, the most productive and efficient state, couldn’t sell into NSW.
Wool was another big headache, for which Mr Kerin partly blamed himself.
The great problem was the old Country Party-initiated Minimum Reserve Price scheme which Mr Kerin — as he later admitted — exacerbated by removing the need for the Wool Corporation to get ministerial approval before setting the reserve price.
In 1988 the corporation set the price at 870¢, which quickly became unsustainable. Over the next two years the corporation spent a $2 billion market support fund, plus $2.5 billion in loans, to buy up what amounted to one year’s production.
Mr Kerin finally forced a reduction to 700¢ but, although hundreds of millions more dollars were spent, the price couldn't be held.
As he later put it: “The buyers looked at the size of the stockpile the industry had bought itself, did its sums, and the MRP collapsed”.
Mr Kerin quit parliament at the 1993 election.
After politics, Mr Kerin held positions on several farm-related bodies, including the meat and livestock corporation.
After growing disillusioned with Labor, he resigned from the party in August 2011 but rejoined the party six months later and was active within the ACT branch — including handing out how-to-vote cards at the 2022 election.