The first Uncle Wiggily story appeared January 10, 1910 in the Newark News. For almost four decades, the newspaper published an Uncle Wiggily story by Garis every day except Sunday, and the series was eventually nationally syndicated. By the time Garis retired from the newspaper in 1947, he had written more than 15,000 Uncle Wiggily stories.

By virtue of his accessible characters and engaging plots, Garis was the one of the most influential children's authors of his day. Many of his books, especially the Uncle Wiggily books, are still widely read and are readily available over the internet. Milton Bradley produced an Uncle Wiggily board game in 1967 and again in 1988. The game debuted much earlier though and remained popular until the 1970s.

Garis wrote many books for the Stratemeyer Syndicate under various pseudonyms. As Victor Appleton, he wrote about the enterprising Tom Swift; as Laura Lee Hope, he is generally credited with writing volumes 4—28 and 41 of the Bobbsey Twins; as Clarence Young, the Motor Boys series; as Lester Chadwick, the Great Marvel series and books featuring Baseball Joe; and as Marion Davidson, a number of books including several featuring the Camp Fire Girls. The couple's children also wrote for Stratemeyer. After Edward Stratemeyer's death in May 1930, his two daughters, Harriet Stratemeyer Adams (1892-1982) and Edna C. Squier (1895-1974), ran the company, with the result that Garis stopped writing for the Syndicate in 1933 after several disagreements.

Garis died in 1962 in Amherst, Massachusetts.

Garis' son, Roger Garis, penned a biography of the writing Garis family My Father Was Uncle Wiggily (McGraw-Hill, 1966). His granddaughter, Leslie Garis, wrote a more revealing memoir, The House of Happy Endings (Farrar, Strauss and Giroux, 2007).

Bed Time series

This series of children's books written by Garis beginning in 1910. Each volume contains 31 stories, one for each day of the month:

1. Sammie and Susie Littletail
2. Johnny and Billy Bushytail
3. Lulu, Alice & Jimmie Wibble-Wobble
4. Jackie and Peetie Bow-Wow
5. Buddy and Brighteyes Pigg
6. Joie, Tommie and Kittie Kat
7. Charlie and Arabella Chick
8. Neddie and Beckie Stubtail
9. Bully and Bawly No-Tail
10. Nannie and Billie Wagtail
11. Jollie and Jillie Longtail
12. Jacko and Jumpo Kinkytail
13. Curly and Floppy Twistytail
14. Toodle and Noodle Flat-Tail
15. Dottie and Willie Flufftail
16. Dickie and Nellie Fliptail
17. Woodie and Waddie Chuck
18. Bobby and Betty Ringtail

Buddy series

This series, following the adventures of Buddy Martyne with his family and friends, was published by Cupples & Leon:

1. Buddy on the Farm or, a Boy and his Prize Pumpkin, 1929
2. Buddy in School, or, a Boy and his Dog, 1929
3. Buddy and his Winter Fun, or, a Boy in a Snow Camp, 1929
4. Buddy at Rainbow Lake, or, a Boy and his Boat, 1930
5. Buddy and his Chum, or, a Boy’s Queer Search, 1930
6. Buddy at Pine Beach, or, a Boy on the Ocean, 1931
7. Buddy and his Flying Balloon, or, a Boy’s Mysterious Airship, 1931
8. Buddy on Mystery Mountain or, a Boy’s Strange Discovery, 1932
9. Buddy on Floating Island or, a Boy’s Wonderful Secret, 1933
10. Buddy and the Secret Cave or, a Boy and the Crystal Hermit, 1934
11. Buddy and his Cowboy Pal or, a Boy on a Ranch, 1935
12. Buddy and the Indian Chief or, a Boy among the Navajos, 1936
13. Buddy and the Arrow Club or, a Boy and the Long Bow, 1937
14. Buddy at Lost River or, a Boy and a Gold Mine, 1938
15. Buddy on the Trail or, a Boy Among the Gypsies, 1939
16. Buddy in Deep Valley or, a Boy on a Bee Farm, 1940
17. Buddy at Red Gate or, a Boy on a Chicken Farm, 1941
18. Buddy in Dragon Swamp or, a Boy on a Strange Hunt, 1942,
19. Buddy’s Victory Club or, a Boy and a Salvage Campaign, 1943
20. Buddy and the G-Man Mystery or, a Boy and a Strange Cipher, 1944
21. Buddy and his Fresh Air Camp or, a Boy and the Unlucky Ones, 1947

Uncle Wiggily series

1. Uncle Wiggily's Adventures
2. Uncle Wiggily's Travels
3. Uncle Wiggily's Fortune
4. Uncle Wiggily's Automobile
5. Uncle Wiggily at the Seashore
6. Uncle Wiggily's Airship
7. Uncle Wiggily in the Country
8. Uncle Wiggily in the Woods
9. Uncle Wiggily on the Farm
10. Uncle Wiggily's Journey
11. Uncle Wiggily and Baby Bunty
12. Uncle Wiggily's Story Book
13. Uncle Wiggily's Picture Book
14. Uncle Wiggily's Puzzle Book
15. Uncle Wiggily on Sugar Island
16. The Uncle Wiggily Book
17. Uncle Wiggily's Bungalow
18. Uncle Wiggily's Picnic Party
19. Uncle Wiggily’s Surprises
20. Uncle Wiggily's Happy Days
21. Uncle Wiggly and The Canoe

Happy Home series

The Happy Home Series is a six-volume series of children's books written by Garis between 1926 and 1927:

1. Adventures of the Galloping Gas Stove
2. Adventures of the Runaway Rocking Chair
3. Adventures of the Traveling Table
4. Adventures of the Sliding Foot Stool
5. Adventures of the Sailing Sofa
6. Adventures of the Prancing Piano