When Paul Tasner was 64, he was called to a meeting with the chief executive of Method cleaning products where he worked as senior director of operations – only to find that the meeting was an exit interview. It was shortly before Christmas 2009; San Francisco felt festive. His wife and friends were waiting for him at a restaurant. “We said our hellos, and I said: ‘I’ve been fired!’ They all laughed.”

Tasner told them he wasn’t joking. “Much was drunk” that night, he says, and instead of feeling anxious about the future, he began to feel good. “I know that’s a weird thing to say, being fired. [But it was] a chance to do some thinking about what comes next.”

He had spent 40 years in manufacturing, packaging and distributing, and had excellent contacts. Consultancy paid the bills but “felt like quietly fading into the woodwork. I wanted to go out with a bang. It was the last chapter in my career. I didn’t want to end it on a boring note. So I put a considerable amount of pressure on myself to find that interesting opportunity.”

Tasner, now 75, says he kept his eyes and ears wide open. “Talking to everybody. Listening. Getting a sense of where the trends were, bouncing ideas off people.” And in 2011, he and co-founder Elena Olivari launched PulpWorks – to design and manufacture packaging made from waste. Its clients range from Google to Campbell’s. Tasner’s TED Talk – on how it’s never too late to reinvent yourself – has had more than 2m views.

Yet when he first had the idea, fundraising was impossible. “Some people were outright crass about it. They didn’t want to loan money to a company headed by somebody my age. ‘You should be retired, enjoying the September of your years’, all this kind of thing.”

At last he was invited to a face-to-face meeting with a potential investor. “I thought: ‘Finally we’ve got a nibble.'” But the investor upbraided him: startups were for younger folk; Tasner should enjoy leisure and family time.

“I said: ‘If we had done this by phone or email I would have been annoyed and upset … But because you called me into your office and you’ve taken half a day out of my precious life, I’m going to remember what an ass you are for the rest of my life.'” He is “quite proud” of that retort.

Ideas for businesses had popped into Tasner’s head throughout his working life. But he had always ruled them out. So, were none of the earlier ideas sound, or was Tasner unable to commit?

“I used the excuse of family and financial obligations, that I really couldn’t be that frivolous. But truth be told, that wouldn’t have held me back,” he says. “My wife would have supported me. The final analysis is that I was afraid.”

As an “impulsive” younger man, Tasner was unable to back his ideas, but did so when he was older and more reflective. “It doesn’t make sense, does it?” he says. But maybe in his case action is borne from slower thought.

“If I had been savvy enough to observe my own reactions, I would have known this many years ago,” he says. In his first big manufacturing job, he had to liaise with “interesting, quirky entrepreneurs. I immediately fell in love with these people. It should have rung a bell for me – this is where you want to be. I should have paid more attention to that.”

PulpWorks is now a decade old, and at work no one mentions Tasner’s age. Yet his personal relationship to it has also changed. “I am proud of who I’ve become. During my 60s I was not really comfortable about my age, about saying: ‘Oh, I’m 64.’ But as soon as I turned, I lost all inhibitions. I’m an old guy! Once you are in your 70s, 70 is not the new 30. You’re 70! I feel totally comfortable about it.”

• Tell us: has your life taken a new direction after the age of 60?