Of American-English origin, the colloquial phrase to get one’s act together means: to organise oneself to undertake or achieve something.

The literal meaning of this phrase is: to get a stage act * ready—from the more general transitive use of to get together in the sense: to organise, put in order, harmonise.

[* Cf. also, with reference to a stage act, the phrase a hard act to follow.]

The earliest literal uses of the phrase to get one’s act together and variants that I have found are as follows, in chronological order:

1-: From The Times (Richmond, Virginia, USA) of Saturday 28^th July 1900 [Vol. 15, No. 143, page 5, column 6]:

The attendance at the Casino has been very good all this week, considering the rain storms, and the bill of vaudeville has proved to be an exceptionally good one. Manager Wells got the acts together in a hurry, and his good judgement saved the reputation of his summer theatre, for there hasn’t been a better bill this season.

2-: From the Democratic Advocate (Greenville, Ohio, USA) of Thursday 9^th January 1902 [Vol. 19, No. 35, page 3, column 1]:

The Whitney Bros. are home for a month’s rest. While they were here during the past summer they worked like beavers getting their new acts together and now they are in for a well-earned and much deserved rest. Their act took like hot cakes in the East, every press notice being fine.

3-: From an interview of Rush Bronson, manager of the Grand Opera House, published in The Indianapolis Journal (Indianapolis, Indiana, USA) of Sunday 23^rd March 1902 [Vol. 52, No. 82; Part 3: page 3, column 3]:

“These vaudeville people have a very unique way of getting an act together. They will pick up queer sayings they hear on the street or about the hotels and work them into their lines. They are very close readers of newspapers. These people are always on the alert for something new, and they keep patching together and changing their speeches until finally their whole act is made up of entirely new sayings.”

4-: From an article about the arrival in Waco of Gentry Bros.’ show, published in The Waco Times-Herald and Telephone (Waco, Texas, USA) of Friday 2^nd October 1903 [12^th Year, No. 265, page 8, column 4]:

Gentrys have been the leaders of trained animal shows for about 19 years and will no doubt be the owners some day of one of the largest circuses in the country.
A real novelty has been added this season, “A Monkey Barber Shop.” A troupe of musical ponies that render beautiful selections with bells. This act took two years to accomplish, but after a tedious length of time the ring master, Mr. Weaver, finally succeeded in getting this act together and at every performance the applause shows for itself that a high class act like this is certainly appreciated.

The earliest transferred uses of the phrase to get one’s act together and variants that I have found are as follows, in chronological order:

1-: From East’s Top Interceptor, Sutherin Looks Ahead To Quiet Cattle Farm, an interview of the Canadian football player Don Sutherin (1936-2022), who was then playing for the Hamilton Tiger-Cats, by Bob Hanley, sports editor, published in The Hamilton Spectator (Hamilton, Ontario, Canada) of Friday 15^th September 1961 [Vol. 116, No. 216, page 20, column 2]—there seems to be a mistake in the way the quotation marks are printed:

In field goal kicking “it’s pretty much up to a man himself. He does most of his practising when the regular practices are over. Down here, Bernie Faloney and Chet Miksa stay with me afterwards so we can get the act together. Remember, it takes three people to do it.”

2-: From an account of the murder trial of Jack Griffith, published in The Miami Herald (Miami, Florida, USA) of Tuesday 25^th February 1969 [59^th Year, No. 87, page 12-A, column 5]—David A. Russell was the defence attorney:

Russell introduced into evidence a letter Griffith received this past December from one of the prosecution witnesses, James (Kenny the Cat) Boyden.
“When he gave it to me, he said I couldn’t get convicted; that he did it,” Griffith said.
WRITTEN IN a mixture of obscenities and adolescent braggadocio, the letter said, “the word is and has been out for a long time that I’m marked—I’ve seen the statements, the transcripts and it makes me sick. Somebody better get their acts together quick.”

3-: From the Wisconsin State Journal (Madison, Wisconsin, USA) of Friday 13^th June 1969 [Vol. 213, No. 72, page 6, column 4]:

Democrats to Seek Reunification at Upstate Convention
By JAMES D. SELK
(Of The State Journal Staff)

The Wisconsin Democratic Party, wracked with intramural warfare since the 1968 presidential primary election, will try to get its act together this weekend at a three-day convention in Stevens point.

4-: From the Wisconsin State Journal (Madison, Wisconsin, USA) of Saturday 16^th August 1969 [Vol. 213, No. 136, page 1, column 7]:

‘Trailer Bill’ Used to Lure Three Rebels
By JAMES D. SELK
(Of The State Journal Staff)

Majority Republicans in the State Senate finally got their act together Friday and passed a relatively austere 1969-71 state budget calling for increased sales and cigaret taxes to meet its $1.562 billion price tag.

5-: From The Atlanta Constitution (Atlanta, Georgia, USA) of Friday 12^th September 1969 [Vol. 102, No. 75, page 6-A, column 1]:

Fire Bombs Ruin Hippies’ Co-Op
By DIANE THOMAS

“No matter who did it, it’s done now and we’re just going to get our act together and start over,” said a petite, broom-toting blonde as she threaded her way through the blackened, water-soaked shell of what had been, until about 5:30 a.m. Thursday when somebody threw a couple of fire bombs into it, a hippie co-operative store called Atlantis Rising.