Martin was born in Weatherford, Texas. Her life as a child, as she describes it in her autobiography My Heart Belongs, was secure and happy. She had close relationships with both her mother and father, as well as her siblings. Her autobiography details how the young actress had an instinctive ear for recreating musical sounds.  Martin’s father, Preston Martin, was a lawyer, and her mother, Juanita Presley, was a violin teacher. Although the doctors told Juanita that she would risk her life if she attempted to have another baby, she was determined to have a boy. Instead, she had Mary, who became quite a tomboy. Her birth was an event as all of the neighbors gathered around Juanita’s bedroom window, waiting for the raising of a curtain to signal the baby’s arrival.

Her family had a barn and orchard that kept her entertained. She played with her older sister Geraldine (whom she called “Sister”), climbing trees and riding ponies. Martin adored her father. “He was tall, good-looking, silver-haired, with the kindest brown eyes. Mother was the disciplinarian, but it was Daddy who could turn me into an angel with just one look”. Martin, who said “I’d never understand the law”, began singing outside the courtroom where her father worked every Saturday night at a bandstand where the town band played. She sang in a trio of little girls dressed in bellhop uniforms. “Even in those days without microphones, my high piping voice carried all over the square. I have always thought that I inherited my carrying voice from my father”.  She remembered having a photographic memory as a child, making it easy to memorize songs, as well as get her through school tests. She got her first taste of singing solo at a fire hall, where she soaked up the crowd’s appreciation. “Sometimes I think that I cheated my own family and my closest friends by giving to audiences so much of the love I might have kept for them. But that’s the way I was made; I truly don’t think I could help it”. Martin’s craft was developed by seeing movies and becoming a mimic. She’d win prizes for looking, acting and dancing like Ruby Keeler and singing exactly like Bing Crosby. “Never, never, never can I say I had a frustrating childhood. It was all joy. Mother used to say she never had seen such a happy child—that I awakened each morning with a smile. I don’t remember that, but I do remember that I never wanted to go to bed, to go to sleep, for fear I’d miss something”.

During high school, Martin dated Benjamin Hagman, before she was packed off to finishing school at Ward-Belmont in Nashville, Tennessee. During that time, she enjoyed imitating Fanny Brice at singing gigs, but she found school dull and felt confined by its strict rules. She was homesick for Weatherford, her family, and Hagman. During a visit, Mary and Benjamin persuaded Mary’s mother to allow them to marry. They did, and by the age of 17, Martin was legally married, pregnant with her first child (Larry Hagman) and forced to leave Ward-Belmont. She was, however, happy to begin her new life. But she soon learned that this life, as she would later say, was nothing but “role playing”.Their honeymoon was at her parents’ house, and Martin’s dream of life with a family and a white-picket fence faded. “I was 17, a married woman without real responsibilities, miserable about my mixed-up emotions, afraid there was something awfully wrong with me because I didn’t enjoy being a wife. Worst of all, I didn’t have enough to do”. It was “Sister” who came to her rescue, suggesting that she should teach dance. “Sister” taught Martin her first real dance—the waltz clog. Martin perfectly imitated her first dance move, and she opened a dance studio. Here, she created her own moves, imitated the famous dancers she watched in the movies, and taught “Sister’s” waltz clog. As she later recalled, “I was doing something I wanted to do—creating”.

Wanting to learn more moves, Martin went to California to attend the dance school at the Franchon and Marco School of the Theatre, and opened her own dance studio in Mineral Wells, Texas. She was given a ballroom studio with the premise that she would sing in the lobby every Saturday. There, she learned how to sing into a microphone and how to phrase blues songs. One day at work, she accidentally walked into the wrong room where auditions were being held. They asked her what key she’d like to sing “So Red Rose”. Having absolutely no idea what her key was, she sang regardless and got the job. She was hired to sing “So Red Rose” at the Fox Theater in San Francisco, followed by the Paramount Theater in Los Angeles. There would be one catch—she had to sing in the wings. She scored her first professional gig, unaware that she would soon be center stage.  Soon after, Martin learned that her studio had been burnt down by a man who thought dancing was a sin. She began to express her unhappiness. Her father gave her advice, saying that she was too young to be married. Martin left everything behind, including her young son, Larry, and went to Hollywood while her father handled the divorce for her. In Hollywood, Martin plunged herself into auditions—so many that she became known as “Audition Mary”. Her first professional audition and job was on a national radio network. Among Martin’s first auditions in Hollywood, Martin sang, ‘Indian Love Call'”. After singing the song, “a tall, craggly man who looked like a mountain” told Martin that he thought she had something special. It was Oscar Hammerstein II. This marked the start of her career.

Mary Martin struggled for nearly two years to break into show business. As a struggling young actress, Martin endured humorous and sometimes frightful luck trying to make it in the world, from car crashes leading to vocal instruction, unknowingly singing in front of Oscar Hammerstein II, to her final break on Broadway granted by the very prominent producer, Lawrence Schwab.  Using her maiden name, Mary Martin began pursuing a performing career singing on radio in Dallas and in nightclubs in Los Angeles. Her performance at one club impressed a theatrical producer, and he cast her in a play in New York, but that production did not open.  She was then cast in Cole Porter’s Leave It to Me!, making her Broadway debut in November 1938. In that production, she became popular on Broadway and received attention in the national media singing “My Heart Belongs to Daddy”. With that one song in the second act, she became a star ‘overnight’.” Martin reprised the song in Night and Day, a Hollywood film about Cole Porter, in which she played herself auditioning for Porter (Cary Grant). “My Heart Belongs to Daddy” catapulted her career and became very special to Martin—she even sang it to her ailing father in his hospital bed while he was in a coma. Martin did not learn immediately that her father had died. Headlines read “Daddy Girl Sings About Daddy as Daddy Dies.” Because of the show’s demanding schedule, Martin was unable to attend her father’s funeral.

She appeared on Broadway in South Pacific, opening on April 7, 1949 as nurse Nellie Forbush. Her performance was called “memorable…funny and poignant in turns”, and she earned a Tony Award. Richard Watts, Jr. of the New York Post wrote: “nothing I have ever seen her do prepared me for the loveliness, humor, gift for joyous characterization, and sheer lovableness of her portrayal of Nellie Forbush…. Hers is a completely irresistible performance.” She opened in the West End production on November 1, 1951. Her next major success was in the role of Peter in the Broadway production of Peter Pan in October 1954, with Martin winning the Tony Award. Martin opened on Broadway in The Sound of Music as Maria on November 16, 1959, and stayed in the show until October 1961. She won the Tony Award for Best Actress in a Musical. The musical gave Martin “the chance to display her homespun charm.” In 1966 she appeared on Broadway in the two-person musical I Do! I Do! with Robert Preston and was nominated for the Tony Award (Leading Actress in a Musical). A national tour with Preston began in March 1968 but was cancelled early due to Martin’s illness.

Although she appeared in nine films in her career, all between 1938 and 1943, she was generally passed over for the filmed version of the musical plays in which she starred. She herself once explained that she did not enjoy making films, because she did not have the “connection” with an audience that she had in live performances. The closest she ever came to preserving her stage performances were her famous television appearances as Peter Pan. The Broadway production from 1954 was subsequently performed on NBC television in RCA’s compatible color in 1955, 1956 and 1960. Martin also preserved her 1957 stage performance as Annie Oakley in Annie Get Your Gun when NBC television broadcast the production live that year.  While Martin did not enjoy making theatrical films, she apparently did enjoy appearing on television, as she did frequently. Her last feature film appearance was a cameo as herself in MGM’s Main Street to Broadway in 1953. Martin made an appearance in 1980 in a Royal Variety Performance in London, performing “Honeybun” from South Pacific. Martin appeared in the play Legends with Carol Channing in a one-year US national tour, opening in Dallas on January 9, 1986.

Mary Martin died a month before her 77th birthday from colorectal cancer at her home in Rancho Mirage, California on November 3, 1990. She is buried in City Greenwood Cemetery in Weatherford, Texas.