Prince Harry and Meghan have set out their goal to "build a better world" in a open letter on the website of their non-profit organisation Archewell.
The Duke and Duchess of Sussex have also announced partnerships between their foundation and several tech and research-focused groups to pursue their aims.
On the home page of the Archewell website is a picture of Diana, Princess of Wales, with son Harry on her shoulders, while in another monochrome image a young Meghan stands as her mother Doria Ragland crouches down to hug her daughter.
In a joint statement, called a "letter for 2021" which overlays the pictures, the couple say: "I am my mother's son. And I am our son's mother. Together we bring you Archewell.
"We believe in the best of humanity. Because we have seen the best of humanity. We have experienced compassion and kindness, From our mothers and strangers alike.
"In the face of fear, struggle and pain, it can be easy to lose sight of this. Together, we can choose courage, healing, and connection. Together, we can choose to put compassion in action.
"We invite you to join us. As we work to build a better world. One act of compassion at a time."
Since stepping down as senior royals in March and moving to the US, the couple have been working towards this moment to officially launch, albeit softly, the website and the philosophy behind their organisation Archewell.
Their decision to leave was based as much about financial as personal freedom.
The huge sums - thought to be well over STG100 million ($A177 million) - they have earned from deals with Spotify and Netflix gives them the capital to pursue their new lifestyle and public goals.
The announcement follows Harry and Meghan's first Spotify podcast on Tuesday which saw their son Archie make his broadcast debut.
However the show has yet to break into the streaming service's top ten most popular podcasts, climbing from 32 to 15.
Commentators have already speculated that Harry and Meghan will have to draw in large audiences if they are to justify the lucrative contract their production company Archewell Audio signed.
Archewell's press secretary said the organisation "uplifts communities through non-profit partnerships and creative activations".
"It's a place where compassion matters, communities gather, and storytelling is the engine.
"The website has been updated to reflect the work Archewell has undertaken throughout 2020 and to create a place for people and communities around the world to share their stories."
Australian Associated Press