Yes, that was McNally Sagal playing Ellen Harrington in a recent Ancestry.com commercial. She has also appeared in a commercial for RealRALiving.com.
Sagal has had several TV roles, most recently Margaret Murphy on FX's Sons of Anarchy. Her character Murphy is a hospital administrator at the hospital where Tara Knowles, Jax Teller's wife works.
McNally is the sister-in-law of Katey Sagal who plays Gemma Teller Morrow on Sons of Anarchy. Another sister-in-law, Liz Sagal, is a writer on the show.
The recent Sons of Anarchy sixth season finale drew 4.67 million viewers, its highest rated finale ever.