Lee McQueen, from Princes Risborough, Buckinghamshire, said he had to take "a deep breath" when the tycoon told him "you're hired" in the hit BBC show.
The 30-year-old beat three other hopefuls to land a £100,000 job alongside Sir Alan.
He said he would buy his girlfriend new shoes with his first pay cheque.
"I'm also trying to negotiate with Alan to see if I can have a holiday in South Africa," he added.
As well as planning to lease a new Porsche, he also said he wanted to help his mother get central heating in her flat.
The series pitches aspiring entrepreneurs to prove themselves in the world of business in the hope of winning a contract to work alongside Sir Alan, who made his fortune after founding technology firm Amstrad.
McQueen was pitched against fellow hopefuls Alex Wotherspoon, Claire Young and Helene Speight in a task to create a men's fragrance.
But Wotherspoon and Speight's efforts were not good enough for Sir Alan, who called McQueen and Young - a retail buyer nicknamed The Rottweiler - back for one final showdown.
Sir Alan told the pair: "Claire, you have some great attributes and Lee, you're very convincing. You are very, very, very convincing. I've concluded... Lee, you're hired."
"When I heard those words 'you're hired' it took a couple of seconds to sink in," McQueen said.
"What swung it for me was when I rolled off my record to Sir Alan. I've been a project manager three times, won three times and never been in the boardroom.
"Claire doesn't need anyone to feel sorry for her but I am gutted for her. I believed at some point that Sir Alan would choose her. She probably went through the biggest journey."
He added: "I'm a big softie and when we learnt we were the final two it was very emotional."
McQueen - who earned £78,000 last year - has been asked by Sir Alan to launch a digital advertising product which will come under one of the tycoon's "portfolio of companies".
He said he was "very ashamed" to have been caught lying on his CV in an episode when he was also hauled over the coals for his poor spelling.
"It lost me some of my integrity," he said.
"I got a good grilling and I deserved it, and I learned from my mistake. It won't happen again
Copyright Speakers Corner 2016