Her maternal great-grandfather, Geoffrey O'Flaherty of Waterford, and great-grandmother Katherine Fitzgerald of County Clare, had left Ireland during the Great Famine.

[3] Her paternal great-grandfather, Phillip McGann, fought for the Union in the Irish Brigade in the Battle of Gettysburg and was shot down defending a stone wall and waving an American flag.

"[10] She had earned a scholarship to Simmons College to study drama, and had been voted "most entertaining girl" in her graduating class at Yonkers High School.

[11] Muir was able to convince the New York World-Telegram to publish a full-page of photographs, which caught the attention of Eleanor Roosevelt, a member of the committee hosting the event.

At the Biltmore Ball, Carl Byoir offered Muir a job publicizing the Roney Plaza Hotel in Miami Beach.

Overnight, she was interviewing people such as Doris Duke, Yvonne Printemps, Pierre Fresnay, Nathaniel Gubbins, Clare Boothe Luce, Errol Flynn, and other notable public figures.

She intended to stay one season, but an offer from the city editor of The Miami News, Frank Malone, to run the rewrite desk gave her pause.

[15] She left the post after the attack on Pearl Harbor, to become publicist for the "Committee to Defend America," and had a radio program called Women in Defense on WQAM during World War II.

[16] During her career, she interviewed and wrote about the Duke and Duchess of Windsor,[17] Jessica Mitford,[18] John Barrymore,[19] Alfred Hitchcock,[20] Joan Crawford,[21] Christina Crawford,[21] Liza Minnelli,[22] Ernest Hemingway,[23] Tennessee Williams,[24] Alan Alda,[25] Lord and Lady Clement Attlee,[26] Larry King,[27] and was one of the first American journalists to interview the Beatles during their visit to Miami Beach to perform for the Ed Sullivan Show at the Deauville Hotel.

Significant productions were performed at the Coconut Grove Playhouse, including Auntie Mame, starring Gypsy Rose Lee, Show Boat, with Julie Wilson, and Waiting for Godot, with Bert Lahr.

Novelist Hervey Allen, distinguished poet, teacher, and author of the bestselling novel Anthony Adverse, called Marjory Stoneman Douglas and Muir, "the Stewart Avenue Gang" because they were neighbors and friends for many years.

[33] In 1962, Frost became ill while visiting Pencil Pines, and asked Muir to guard his satchel of poems while he was being treated at Baptist Hospital.

In 1953, she wrote the first edition of Miami, U.S.A. [36] When it first appeared, Marjory Stoneman Douglas said in the Chicago Tribune, "Only old American cities have been thought to be worthy subjects of books.

The story, with the inspired title, is vigorous, colorful, dramatic, variously detailed, jam-packed with people, fast moving, a seething document.

[38] In 1987, she authored the first edition of Biltmore: Beacon for Miami, a history of the historic Coral Gables hotel built by George Merrick.

[43] Muir was inspired to build the children's book collection of the Coconut Grove Library as a memorial to her youngest daughter, Melissa, who was tragically killed by a delivery truck while playing in a friend's front yard just before her fifth birthday.

[44] She joined the Coconut Grove Library board of directors, that met in her home annually to discuss the collection and the condition of the building.

[45][46] Muir was appointed to the board of trustees for the City of Miami's Public Library in 1962, at the recommendation of county commissioner Alice Wainwright.