Scorsone - who plays Dr. Amelia Shepherd on the medical drama - told TV Guide that she was pleased with her promotion.
"It's so fantastic for so many reasons," she said. "The set is really a wonderful environment. Everyone is generous and fantastic, so to know that's going to be my home for a while is pretty nice."
Scorsone's character is sister to Grey's Anatomy doctor Derek Shepherd (played by Patrick Dempsey), though the pair have never been seen together on screen.
The actress revealed that she is keen to work with Dempsey, saying: "It is a little bit intimidating, knowing how passionate people are, wanting to honour their expectations in the relationship with Derek, who is so deeply a part of people's emotional journey on this show."
Shonda Rhimes, creator of both series, confirmed that a meeting between the two characters is in the works.
"We've absolutely been talking about that," she said. "Based on the history we've already established between Amelia and Derek, there definitely has to be some sort of encounter at some point."
Private Practice will return to ABC for a fourth season on September 23.