LONDON — Celebrity hairstylist Sam McKnight’s portfolio can rival history books.

In his chair, he has transformed Princess Diana, Madonna, Lady Gaga and Tilda Swinton. Then there’s his work for Chanel, Fendi, Balmain and Burberry.

McKnight’s five-decade career calls for a celebration and on Tuesday evening, he didn’t just toast his accomplishments, but his 70th birthday and his MBE, or Member of the Most Excellent Order of the British Empire from King Charles.

The hairstylist drew in a star-studded crowd at the restaurant La Môme, many of whom he calls friends and colleagues, including Kate Moss, Kristen Scott Thomas, Tom Ford, Stella McCartney, Charlotte Tilbury and Paul Smith.

Here, McKnight recounts his most memorable moments in the industry, lessons in starting his own beauty brand and words of wisdom to his younger self.

WWD: What’s a memorable hair journey from your career?

Sam McKnight: That’s a hard one to take away, but a lot of the travel with Princess Diana was amazing, such as going to the Taj Mahal in India, the refugee camps in Pakistan and Mother Teresa at the Vatican. It was all places I would never have been able to go to if I hadn’t been part of that.

Being around in the ‘80s in New York was pretty amazing because it was the beginning of the supermodels era and that really informed the rest of my life because it was the beginning of the fashion industry as we know it. 

I met so many people and lots of us started off together, like Bobbi Brown, François Nars and Laura Mercier. The brilliant thing about it all is that I’m still really good friends with the people I worked with to this day. Don’t make any enemies at the beginning of your career because they’re still going to be around you.

WWD: Do you remember the day you gave Princess Diana her famous haircut?

S.M.: It was on a photo shoot for Vogue with Patrick Demarchelier and by then I’d been working with Vogue for 13 years. It was July 1990 and it was the day before we were going to Paris to shoot couture — there was a change in the air in the pages of the glossy magazines. The big hair and flouncy clothes were gone for us and Princess Diana was also just coming out of that.

She said to me, “What would you do [with my hair]?” and I said I’d cut it all off and start again. 

Then Anna Harvey, her stylist at the time, and I introduced her to Gianni and Donatella Versace, who started making her those color-blocked business suits. She went from the romance of the ‘80s into the business of the ‘90s.

Before she died, she was growing her hair out and it had gone into a softer thing and it was still looking great. I don’t think she would’ve ever had long hair because it was really quite thick and unmanageable, and she couldn’t be bothered. She wasn’t a fashion or beauty victim — she just wanted to look good and presentable for the charities she was doing, it was all about that and the kids.

WWD: Another famous haircut you’ve done is Tilda Swinton’s buzzcut, how did that happen?

S.M.: Tilda was doing press for the film “Michael Clayton” and she had longer hair. If I remember correctly, the American PR for the film were trying to get her to appear soft, warm and cozy for the Oscar nomination run. 

We got in the bathroom and I was cutting her hair, she said, “Should we go really short?” I said yes and we eventually buzzed it and she still has the same hair to this day, but I think that was very her and being the rebel. She brings her own energy to everything she does and she’s never like anyone else.

WWD: You also did Madonna’s hair for her “Bedtime Stories” album cover, what do you remember from that photo shoot?

S.M.: We were in a really tacky Miami hotel that has French Provencal decor, where the blues were just too blue and the pink just too pink. We did a couple of days shooting in the hotel bedrooms and hallway. She was really fantastic and I have to say, she could not have been nicer. My one regret in my whole career is that it was her birthday and she invited us all to her house when she lived on an island near Miami Beach, but I had to go back to New York to do a Vogue shoot. I could have been late for the Vogue shoot, or the one time I could have just canceled, but I never got invited to another birthday party.

WWD: Another famous musician you’ve worked with is Lady Gaga, what was that like?

S.M.: One of my greatest memories is doing the MTV Video Music Awards with her. I had to pin a steak onto the top of the wig and that was probably the most unusual thing I’ve ever done. There were a lot of flies in the bathroom and then a few hours later, we shot a video with Nick Knight for Tom Ford.

WWD: You started your beauty brand Hair by Sam McKnight in 2017, where did that business idea come from?

S.M.: I had been trying to do it and at the same time I had been advising other brands for many, many years, then suddenly, as I’m getting older, I was like, “Why am I doing this? Why don’t I just do my own thing?” I don’t have to go through layers of bureaucracy and we can just do what we want to do without any restrictions.

I funded it myself and we started off with four styling products. We’ve expanded a lot and my life is moving toward much more of that because it takes a lot of time and I’m thoroughly enjoying it.

WWD: How does it feel to go from being so creative all the time to putting on your business hat?

S.M.: There’s always been a business side to it even when we’re doing all the creative stuff. It’s not just turning up with a bunch of wigs and flogging it. It’s been a business since I was 20 years old, but retail is a different thing and it needs different skills. I have a few more people on the team now because before it was just two of us. We’re nine people now and we have 25 products; we’re going from strength to strength.

WWD: What have you learned about retail?

S.M.: I’ve learned that retail is really difficult and it’s really all about the customer because on the creative side, it’s all about us and what we do, but on the retail side of it, it’s all about the customer and keeping them interested, satisfied and acquiring [new] customers. I’ve really enjoyed it and [it’s no different from] when I was working with Chanel or Fendi, they were my customers, so I had to keep them happy and it’s a continuation of that.

WWD: What has starting your own beauty brand taught you?

S.M.: It’s not so much taught me, but more about putting into practice what I’ve learned over the last 50 years. The lessons that I’ve learned about resilience, having faith in your own guts, and not wavering and taking people’s opinion on board, but also discarding it if you want to. It’s about listening to people and working in tight budget restraints.

WWD: You’re quite the workaholic, where does that drive come from?

S.M.: Never being on the same job for more than a few days has really kept me alive for the last 50 years and I think adding products into the mix has been the challenge I’ve needed.

I am a workaholic, but I do like to spend a lot of time in the garden. I’ve also got a dog now, so I spend a lot of time going on long dog walks and spending time planting in the garden. I have a balance now.

WWD: What words of wisdom would you give to your younger self?

S.M.: As I get older, I’m more aware of things and better at time management. I’ve learned to save my energy for the things that need to be done — that’s what I would tell my younger self, but it’s only with the passage of time that you understand the importance of slowing down, breathing and taking a bit of space. I’ve done yoga for the last 20 years and I’ve learned to breathe. Gardening is also part of that meditation. 

WWD: How did you get into gardening?

S.M.: I used to live in Maida Vale and on [summer] evenings, I would go to the Rose Gardens in Regent’s Park to sit and read as the sun went down. When I found my current house, I said I’d take on gardening as a project, thinking it would take me six or seven years, but we’re now 15 years in. The garden brings me such joy and inspiration — our new scalp oil is completely garden inspired and it’s 98 percent natural. We’re the first to have this pipette, which is made out of mushrooms. There’s no glass or plastic and it completely breaks down anywhere, you don’t have to put it in compost.

Not only is the garden meditative, but I can’t not think about business and hair, even when I’m in the garden thinking I’m meditating, I’m actually constantly looking at colors and wondering what color we can use for the packaging.