The win was his 24th in 45 career starts.
But his career has been interrupted by leg problems since he won the NSW Derby three years ago.
He is trained by David Aiken and the win was Alford's second Inter Dominion as a driver after partnering Golden Reign to win at Addington in 1995.
"I couldn't afford to give the parked position away so I had to make a stand early and it paid off," said Alford.
"It is a credit to the job David has done with this horse and he is a wonderful animal, I just love him."
Lennytheshark was as long as $16 on the New Zealand TAB fixed odds two months ago but was favourite for the series from the time Beautide and Christen Me pulled out last month.
He can now return to his beloved Melton track for the Victoria and Hunter Cups in February before a possible meeting with Christen Me and Beautide at the Miracle Mile in Sydney in March.
The disappointment of the final was second favourite Philadelphia Man, who had a good run midfield but never made any ground when asked to go at the bell.
Earlier in the meeting, former Auckland pacer Beaudiene Boaz won the A$200,000 Golden Nugget for 4-year-olds, leading all the way.