Leona Lansing, portrayed by Jane Fonda, is a character (CEO of a media conglomerate), not unlike Ted Turner, Fonda's third husband from 1991-2001. In the first episode which Fonda appears in, there is a conversation, among other characters, about a comparison between the "Tea Party" circa 2010s, and "leftist radicals" circa 1960s, and one of the names mentioned as one of the leftist radicals is "Hayden," which refers to Tom Hayden, who was Fonda's second husband, from 1973-1989.
In Sorkin's world ACN stands for Atlantis Cable Network. There is a real life ACN in Canada which provides Internet and telephone services, and there was an ACN cable network in the US. It was "America's Collectibles Network" and sold everything from knives and watches to cosmetics and jewelry. In 2000 they changed their name to Jewelry Television. Seen in 80 million homes, they still use the ACN name legally and on signage at their broadcast location in Knoxville, TN.