Kicking off the action on Centre Court on day two, the German eased to a 6-4 6-3 win over her compatriot in front of the watching Duchess of Cambridge in the Royal Box.
Despite not winning a tournament since beating Serena Williams in the final at SW19 last year, Kerber has shown some good recent form, including reaching the final in Eastbourne last week.
And the 31-year-old, who lost her only previous meeting with Maria, avoided becoming the first ladies' champion to be defeated in the first round the following year since Steffi Graf in 1994.
Kerber said: "I was really nervous, to be honest, because of course going out there as the defending champion, it was really special.
"Walking on the Centre Court, playing there again, I mean, a lot of emotions, a lot of memories.
"But I was enjoying this. I was really enjoying the match. I was enjoying the points and the crowd. It was a really nice match, but of course with a lot of nerves at the beginning."
World number one Ashleigh Barty eased into the second round courtesy of a 6-4 6-2 victory over Saisai Zheng.
The Australian, who won this year's French Open, has fond memories of the All England Club after winning the girls' singles title in 2011.
She is one of the favourites to make it back-to-back grand slams here and laid down an early marker on Court One.
Barty said: "Yeah, I think a very tricky opponent to start off with. I am very happy with the way we were able to work our way into the match.
"It took some time to adjust to conditions and a different court. It's a beautiful court to play on."
British number one Johanna Konta battled into the second round with a 7-5 6-2 victory over Romanian qualifier Ana Bogdan.
She said: "It was very tough out there. I don't think either of us felt quite comfortable, we were both trying to find our feet.
"First rounds are never easy and I'm really pleased to have competed through. So far in the season I feel like I'm building in every match I'm playing."
Former champion Garbine Muguruza was the victim of a big shock as she was beaten in straight sets by Brazilian Beatriz Haddad Maia.
The 2015 winner and former world number one, who has fallen down the rankings in the last two years, was beaten 6-4 6-4.
Ex-US Open champion Sloane Stephens won her first match at the All England Club since 2016, beating Timea Bacsinszky 6-2 6-4 on Court 2.