Serena's demolition of Elena Vesnina in the day's first semi-final had set up the prospect of a first all-Williams Wimbledon final since 2009.
But Kerber had no intention of being a footnote in Wimbledon history and she saw off five-time champion Venus in 71 minutes on Centre Court to reach her first All England Club title match.
"Venus won so many times here and was playing really well. That's why I'm so happy to reach my first Wimbledon final," Kerber said.
"It's a really good feeling. I'm really enjoying my tennis life."
Kerber stunned Serena to win her maiden Grand Slam crown in the Australian Open final in January and the 28-year-old again stands in the way of the world number one's bid to win a record-equalling 22nd major.
Having beaten one Williams, the fourth seeded Kerber can set her sights on becoming the first player to defeat both of the American siblings in the same Grand Slam since Kim Clijsters at the 2009 US Open.
"It's a completely new tournament and surface. I will just try to go out with a lot of confidence and play my best tennis," Kerber added.
If she can cause another upset against six-time champion Serena, Kerber would become the first German woman to win Wimbledon since Steffi Graf in 1996.
Kerber couldn't be in better form heading into Saturday's final.
She had raced through her six matches at Wimbledon without dropping a set, now has WTA tour-best 34 match wins in 2016 and is guaranteed to rise to a career-high second in the world rankings next week.
Venus had become a sentimental favourite at the All England Club over the last fortnight as she returned to the last four of a Grand Slam for the first time in six years after a long battle with Sjogren's syndrome, an illness that causes fatigue and joint pain.
Mastery
The 36-year-old had won all eight of her previous Wimbledon semi-finals dating back 16 years to her maiden appearance in the last four when she defeated Serena.
But in her first All England Club semi-final for seven years, Venus -- the oldest woman to make the last four since Martina Navratilova in 1994 -- was unable to roll back the years one more time.
Kerber landed the first blow with a break in the opening game, but Venus hit straight back with a break of her own.
Angelique Kerber celebrates her win against Venus Williams.
It was six games before Kerber managed the first successful service hold of the match.
That proved a crucial moment as she pressed home her advantage with a fourth successive break.
Venus finished the first set with more aces and as many winners as Kerber, yet an unusually high total of 12 unforced errors had proved decisive.
Kerber held a 3-2 edge in her previous meetings with Venus and the German was well on course to maintain her mastery of the seven-time Grand Slam champion when she broke in the first game of the second set.
Despite looking emotionally and physically drained by her longest run at Wimbledon for seven years, Venus didn't throw in the towel.
But her dreams of a first major title since 2008 were finally put to rest when Kerber unleashed one last crunching cross court winner.
Serena thrashes Vesnina
A Champagne cork popped somewhere on Centre Court four games into Serena Williams's Wimbledon semi-final and while it was a tad premature, her 6-2 6-0 thrashing of Elena Vesnina suggested she could celebrating something special come Saturday.
The top-seeded American will be taking nothing for granted, having seen her bid to match Steffi Graf's modern era record of grand slam titles stuck one short on 21 for a year, but it was a menacing show of strength, albeit against an overawed opponent.
She dropped only three points on serve in an embarrassingly one-sided 49 minutes -- crunching down one 123mph delivery that topped the women's speed charts at this year's tournament.
From the moment the 34-year-old nonchalantly broke serve in the opening game the writing was on the wall for a leaden-footed Vesnina appearing in her first grand slam semi-final.
By the time the latecomers took their seats two games later Serena was 3-0 ahead and her place in a ninth Wimbledon title already looked in the bag.
Vesnina held serve twice in the opening set, prompting sympathetic applause, but the world number 50 was swept aside in the second set, winning only five points, as Serena marched to singles victory number 85 at the All England Club.
