It hasn't been an easy journey in a white-dominated sport steeped in tradition, but Williams has pursued her goals with a determination just as fearsome as the raw power with which she plays her shots.
Strong but also quick, ruthless and fiercely competitive, Williams has been at the top for a generation, since she beat Martina Hingis aged 17 in the 1999 US Open final.
So often she has been more or less unbeatable, and even at the age of 35 she remains the favourite whenever she plays, her capacities not noticeably diminished.
Venus, 14 months older at 36, is her greatest rival and she can also take much credit for her success, after so many years touring and practising together and encouraging each other.
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But it's a lop-sided head-to-head: out of their nine major finals, Serena has won seven and her overall win-loss record against her big sister is 17-11.
But don't bet against the newly engaged Williams, showing a refreshingly carefree spirit this year, also sealing the calendar-year Grand Slam which narrowly eluded her in 2015.
It's all a long way from the pitted courts, sometimes missing nets and with gunshots audible nearby, of Compton in Los Angeles, where Williams practised with Venus from the age of five.
The youngest of five daughters was drilled intensely by her father, former sharecropper Richard Williams, who was happy to let schoolchildren hurl insults at his girls as they played.
Richard and Oracene Williams moved their family to Florida in the early 1990s, seeing their daughters needed more specialist coaching, with Serena already an outstanding junior.
She turned professional in 1995, at the age of just 14. Two years later, she was in the top 100 and in January 1998 made her Grand Slam debut, reaching the second round of the Australian Open -- where she was beaten by Venus.
And so it was fitting that when Serena's crowning glory came, in the same place where her Grand Slam career started 19 years earlier, Venus was the first to congratulate her across the net.
"This is a story," Serena said. "This is something that I couldn't write a better ending. This is a great opportunity for us to start our new beginning.