The 26-year-old recruitment manager was hired by Lord Alan Sugar to become his new business partner over runner-up Tom Gearing, with fellow finalists Nick Holzherr and Jade Nash being fired earlier.
Sugar will now make a £250,000 investment into Martin's business idea, a recruitment agency specialising in science and technology.
The four candidates faced interviews with the entrepreneur's colleagues Claude Littner, Margaret Mountford, Mike Soutar and Matthew Riley.
The final boardroom saw Lord Sugar picking between Martin and Gearing, before concluding: "It's a very, very difficult moment for me right now. You're both credible people to invest money in, so is it the devil or is it the safety? And I should keep to my ethos of keeping it simple, keeping it straightforward. So Ricky you're going to be my business partner. Ricky, you're hired."
Martin said: "Lord Sugar and I are going to be a powerful force to reckon with. I can't say I've digested it yet. I'm ecstatic. Genuine shock, I'm so, so pleased. Tom is incredible at what he does, great competition but I believed in myself, I thought I always I had it in me and I proved it."
Runner-up Tom Gearing added: "If I was going to lose to anyone, I was happy it was Ricky. He was such a strong and credible candidate. We had some amazing experiences, I met some really good people, it was fantastic, and I have no regrets about it at all."
The interviews included Mike Soutar enquiring why he decided to go by the name 'Ricky Martin', while Claude Littner described his personal statement as "crass, obnoxious and infantile".
However, of Martin's business plan, Littner said: "I read your business plan and I was quite impressed. It was interesting, well-written and you've done very well in your career."
Before Lord Sugar made his final decision, Karren Brady told him: "Ricky has got great credibility in the field. He's the one that has changed the most over the process."
Claude Littner added: "I've got to say, I'm mesmerised by the guy."
Ricky Martin follows last year's winner Tom Pellereau, who became Lord Sugar's first business partner through the BBC One show.