"We had a big night celebrating, that’s for sure.
"A guy in the States asked me if this was a dream come true, and I said it kind of wasn’t because it seemed just so unfathomable that I could win it — it was out of the realms of possibility.
"It’s not a dream come true.
"It’s more than that.
"Considering it’s the first time I’ve done this, it’s pretty surreal, to be honest."
Late last year, public voting began and his motorcycle was whittled down to one of six finalists selected to attend the show in California this month, where the winner would be announced.
Now he is officially the first person outside the United States to be crowned as champion.
Mr Martin said the competition was like "the Super Bowl" of custom motorcycle building, and gave public exposure to non-professional bike builders and restorers.
First prize was a cheque for $US10,000 ($NZ16,480) and a "massive belt" resembling those given to boxing champions.
He said it took about two and a-half years to build his world champion bike, which started when he acquired a vintage 1948 Harley-Davidson panhead engine and frame.
"It’s really fun to ride and sounds awesome ripping along.
"It handles great and rides like an arrow at 75 miles per hour [120kmh] — the brakes even work well, which was a nice surprise."
He said it cost about $60,000 to build and there was about 700 hours of labour in it.
"The nice prize money didn’t touch the sides."
Despite having a bit of clout behind his name now, the software engineer said he was not yet totally committed to making a career change and becoming a professional motorcycle builder and customizer.