The ad opens with home-video footage of William's ultrasound and recovery after a difficult birth, and shows scenes of her breastfeeding, pumping and running around after Alexis as a toddler.
The video then shows Williams speaking out about her first U.S. Open win in 1999: "Everyone's just so supportive, and that really helped me. It's not like it came easy, I really had to work. I've been practicing so long for this moment, and it came, and it's here."
According to Muse, the commercial aims to reignite conversations around motherhood using the #ThisMama hashtag and to shine a light on the incredible strength of mothers, using Williams as the embodiment of this strength.
"As both a nurturing mother and a fierce competitor, no matter what, she keeps going," said agency strategy director Sarah Garman to Muse.
Meanwhile, Williams has also recalled the greatest gift of all: her father's love and devotion and iron will to ensure Serena and Venus became the most successful siblings in sport's history.
Only now, after bringing her own daughter into the world, does Williams have a full perspective of the sacrifices her father and lifelong coach Richard made for her.
"My dad is amazing. I could never have done what he has done, not only with myself but with Venus," the American told ESPN. "It's shocking and as a parent to do something every single day is very difficult - and I can't do something with my daughter every single day.
"And I remember when we were young we went out and trained and practised and we didn't miss a day.
"To have that discipline actually makes me look at myself as a player, as a parent and just really appreciate my dad so much more than I ever have in the past.
"It just makes me see it totally different and I love him to death and he's watching all my matches and he's probably already texting me right now saying 'Serena, you need to do this a little more'.
"And I'm like 'okay, Dad, I got this."
Williams has also got another golden opportunity, perhaps her best yet, to equal Margaret Court's all-time record number of singles slams in New York.
The only major champion left in the draw, the eighth seed plays world No.5 Elina Svitolina on Wednesday night for a place in the final for a 10th time at Flushing Meadows.
"It feels good. It feels like, okay, this is what I've been training for," Williams said.
"This is how hard I've been working. It feels like, you know, hard work pays off when that happens."
AAP with Heidi Krause