He was born in Homestead, Pennsylvania into a family of actors on May 23, 1898. His father, "Cutie" McHugh, acting in the play Of Human Hearts, had set the record for acting for the longest amount of time in a single play. Frank's parents owned their own stock company, so he spent his childhood traveling and acting with them. He had made his debut on the stage at the tender age of six. His siblings also acted in the troupe run by their parents. The oldest brother, Jim, usually got the leading roles, while the younger siblings, Matt, Kitty, Eddie, and Frank, the baby of the family, usually played the supporting parts. The McHugh's company toured around the country putting on a wide variety of plays ranging from comedy to drama and everything in between. When in his late teens, young Frank joined the Marguerite Bryant Stock Company as the resident juvenile. After this, he continued to do stock theatre and travel the vaudeville circuit.

In 1925, he got his first role on Broadway in The Fall Guy with Ernest Truex. Later he traveled to London as the stage manager of James Gleason's hit play Is Zat So? starring Gleason and Robert Armstrong. On his return from London, he met actor Pat O'Brien at his brother Jim's party welcoming him back to New York. At the time O'Brien had been in the same company as Jim McHugh, and they were later to share a room together in Manhattan. O'Brien was good friends with Jim, but he was to become even closer friends with Jim's baby brother. Soon after their first meeting McHugh and O'Brien both got jobs in the play Tenth Avenue, which played in Baltimore and had in it their mutual friend Spencer Tracy.

McHugh's first role in a movie came in 1928, three years after his Broadway debut, in a Vitaphone short subject. Two years after this, he headed out to Hollywood and was signed as a contract player for Warner Brothers. His first movie in Hollywood was The Dawn Patrol, starring Richard Barthelmess and Douglas Fairbanks, Jr. McHugh played the small part of Flaherty, a World War I motorcycle messenger. A year and many small parts later he acted in the classic The Front Page, the first of fourteen films he was to do with friend Pat O'Brien. Altogether, he acted in more movies with O'Brien than with any other actor. In 1932 he got to act with two more of his close friends, Joan Blondell and James Cagney, in The Crowd Roars. (He reprised the same role in the 1939 remake of The Crowd Roars, Indianapolis Speedway, starring Pat O'Brien in Cagney's old role.) McHugh had first met Cagney in 1928 at a Lambs Club frolic in New York. They saw each other occasionally after that, but it was not until acting together on this picture that they became close and found they had a lot in common. McHugh, Cagney, and O'Brien were all to work together in the 1934 film, Here Comes the Navy. In this film McHugh plays Cagney's friend and sidekick, as he was to do in many more early Warner Brothers pictures. The trio worked together several more times. In 1936 McHugh got his first and only leading role in a movie in Three Men on a Horse, playing a common greeting card writer, who gets kidnapped by three horse-racing gamblers. One of the three gamblers in the film was Allen Jenkins, a Warner's regular, who was to work with McHugh in a grand total of twelve movies over the years.

By this time McHugh was a well-established character actor, known most for his touches of comedic relief in otherwise serious films. He continued to work hard at Warners. In the meanwhile, he had gotten married to Dorothy Spencer from Kentucky. He remained married to her for the rest of his life. Together they had two sons and a daughter. Unfortunately one of their sons was later killed. McHugh's friends were there to support him in that time of tragedy.

In 1937, McHugh was in the documentary style Navy film Submarine D-1. The next yeear he played the husband of one of the daughters in the extremely popular movie Four Daughters. He reprised this role in later sequels: Four Wives (1939) and Four Mothers (1941). McHugh starred in The Roaring Twenties, with Cangey and Humphrey Bogart in 1939. Toward with beginning of the film, the story called for a reunion between veteran Cagney and his friend McHugh. This scene was very dull as written in the script, so when McHugh suggested a different scenario for the scene the director quickly jumped at the idea, and it was McHugh's version that was filmed. In The Fighting 69th a year later, he once again suggested a scene that was used in the film. This time he devised the ending of the movie.

During World War II, his movie making slowed considerably, but he still kept himself busy. In 1942 he was a member of the Victory Caravan, which consisted of a large band of actors traveling across the country selling war bonds. Also during the war years he occupied a lot of his time making guest appearances on the popular radio shows of the day, including Bing Crosby's Kraft Music Hall radio show on NBC, where he was a frequent guest.

It was during this period that he broke ties with Warner Brothers and started working at various other studios. In 1944 he played Father Timothy O'Dowd, one of his most popular roles, in Paramount's Academy Award winning film, Going My Way. In 1949 he was in Mighty Joe Young, playing Robert Armstrong's assistant, Windy. Around this time his parts began to thin out even more. He was in the notable classic The Last Hurrah, with his old friends Spencer Tracy and Pat O'Brien in 1958. For the 1964-65 season McHugh was a regular on the Bing Crosby television show. He played Willis Walter, a friend of the Crosby family who is constantly imposing on them. Three years after The Bing Crosby Show. McHugh was to appear in his last movie Easy Come, Easy Go as Captain Jack. After this he retired to Cos Cob, Connecticut. He died on September 11, 1981 at the age of eighty-three. Soon after his death, James Cagney said about his old friend, "Frank, dear Frank. Of all our gang, Frank was the funniest one, and the only people who saw him at his funniest were the boys down at The Players and The Lambs. He'd take those skinny little parts they gave him at Warners and make them little bits of comic genious. I saw him just a few days ago on television in the musical version of State Fair, a nothing part, and Frank made it bloom with his charm. An actor."

Sources: Cagney (1997) by John McCabe
The Wind at My Back (1964) by Pat O'Brien
Cagney by Cagney (1976) by James Cagney
Cagney (1974) by Michael Freedland
and various other web pages