After having collected enough poems for a book, Service "sent the poems to his father, who had emigrated to Toronto, and asked him to find a printing house so they could make it into a booklet. He enclosed a cheque to cover the costs and intended to give these booklets away to his friends in Whitehorse" for Christmas. His father took the manuscript to william Briggs in Toronto, whose employees loved the book. "The foreman and printers recited the ballads while they worked. A salesman read the proofs out loud as they came off the typesetting machines." An "enterprising salesman sold 1700 copies in advance orders from galley proofs." The publisher "sent Robert's cheque back to him and offered a ten percent royalty contract for the book."

Whitehorse was a frontier town, less than ten years old. Located on the Yukon River at the White Horse Rapids, it had begun in 1897 as a campground for prospectors on their way to Dawson City to join the Klondike Gold Rush. The railroad that Service rode in on, the White Pass and Yukon Route, had reached Whitehorse only in 1900.

In 1899, Service was a store clerk in Cowichan Bay, British Columbia. He mentioned to a customer (Charles H. Gibbons, Editor of the Victoria Daily Colonist) that he wrote verses, with the result that six poems by "R.S." on the Boer Wars had appeared in the Colonist by July 1900 – including "The March of the Dead" that would later appear in his first book. (Service's brother, Alick, was a prisoner of the Boers at the time. He had been captured on November 15, 1899, alongside Winston Churchill.)

The Colonist also published Service's "Music in the Bush" on September 18, 1901, and "The Little Old Log Cabin" on March 16, 1902.

In 1903, down on his luck, Service was hired by a Canadian Bank of Commerce branch in Victoria, British Columbia, using his Commercial Bank letter of reference. The bank "watched him, gave him a raise, and sent him to Kamloops in the middle of British Columbia. In Victoria he lived over the bank with a hired piano, and dressed for dinner. In Kamloops, horse country, he played polo. In the fall of 1904, the bank sent him to their Whitehorse branch in Yukon. With the expense money he bought himself a raccoon coat."

Throughout this period, Service continued writing and saving his verses: "more than a third of the poems in his first volume had been written before he moved north in 1904."

Service's book, Songs of a Sourdough, was "an immediate success." It went through seven printings even before its official release date. Ultimately, Briggs "sold fifteen impressions in 1907. That same year there was an edition in New York, Philadelphia, and London. The London publisher, T. Fisher Unwin, struck a twenty-third printing in 1910, and thirteen more by 1917." "Service eventually earned in excess of $100,000 for Songs of a Sourdough alone" (equal to about $2.6 million today after inflation).

Following his leave, in 1908 the bank transferred Service to Dawson, where he met veterans of the Gold Rush, now ten years in the past: "they loved to Reminisce, and Robert listened carefully and remembered." He used their tales to write a second book of verse, Ballads of a Cheechako, in 1908. "It too was an overwhelming success."

Robert Service lived from 1909 to 1912 in a small two-room cabin on 8th Avenue which he rented from Edna Clarke in Dawson City. His prosperity allowed him the luxury of a telephone. Service eventually decided he could not return to Dawson, as it would not be as he remembered it. He wrote in his autobiography:

Service left Dawson City for good in 1912. From 1912 to 1913 he was a correspondent for the Toronto Star during the Balkan Wars.

In 1913, Service moved to Paris, remaining there for the next 15 years. He settled in the Latin Quarter, posing as a Painter. In June 1913, he married Parisienne Germaine Bourgoin, daughter of a distillery owner, and they purchased a summer home at Lancieux, Côtes-d'Armor, in the Brittany region of France. Thirteen years younger than her husband, Germaine Service survived him by 31 years, dying aged 102 in 1989.

Service was 41 when World War I broke out; he attempted to enlist, but was turned down "due to varicose veins." He briefly covered the war for the Toronto Star (from December 11, 1915, through January 29, 1916), but "was arrested and nearly executed in an outbreak of spy hysteria in Dunkirk." He then "worked as a stretcher bearer and ambulance driver with the Ambulance Corps of the American Red Cross, until his health broke." Convalescing in Paris, he wrote a new book of mainly war poetry, Rhymes of a Red Cross Man, in 1916. The book was dedicated to the memory of Service's "brother, Lieutenant Albert Service, Canadian Infantry, Killed in Action, France, August 1916." Robert Service received three medals for his war service: 1914–15 Star, British War Medal and the Victory Medal.

In the 1920s, Service began writing thriller novels. The Poisoned Paradise, A Romance of Monte Carlo (New York, 1922) and The Roughneck. A Tale of Tahiti (New York, 1923) were both later made into silent movies. During the winter season, Service used to live in Nice with his family, where he met British Writers, including H.G. Wells, A.K. Bruce, Somerset Maugham, Rex Ingram, Franck Scully, James Joyce, Franck Harris, and Frieda Laurence, who all spent their winters in the French Riviera, and he wrote that he had been lucky to have had lunch with Colette.

With the end of the war, Service "settled down to being a rich man in Paris.... During the day he would promenade in the best suits, with a monocle. At night he went out in old clothes with the company of his doorman, a retired policeman, to visit the lowest dives of the city". During his time in Paris he was reputedly the wealthiest author living in the city, yet was known to dress as a working man and walk the streets, blending in and observing everything around him. Those experiences would be used in his next book of poetry, Ballads of a Bohemian (1921): "The poems are given in the persona of an American poet in Paris who serves as an ambulance driver and an infantryman in the war. The verses are separated by diary entries over a period of four years."

In 1926, Archibald MacMechan, Professor of English at Canada's Dalhousie University, pronounced on Service's Yukon books in his Headwaters of Canadian Literature:

Service's first novel, The Trail of '98, was made into a movie by Metro-Goldwyn-Mayer, directed by Clarence Brown. "Trail of '98 starring Dolores del Río, Ralph Forbes and Karl Dane in 1929 ... was the first talking picture dealing with the Klondike gold rush and was acclaimed at the time by critics for depicting the Klondike as it really was."

In 1930, Service returned to Kilwinning, to erect a memorial to his family in the town cemetery. He also visited the USSR in the 1930s and later wrote a satirical "Ballad of Lenin's Tomb". For this reason his poetry was never translated into Russian in the USSR, and he was never mentioned in Soviet encyclopedias.

Service lived in Monaco from 1947 to 1958. He wrote two volumes of autobiography – Ploughman of the Moon (1945) and Harper of Heaven (1948). He died in Lancieux and is buried in the local cemetery.

Service wrote prolifically during his last years, publishing six books of verse from 1949 to 1955. A book he had written in 1956 was published posthumously. In the spring of 1958, not long before Service died, Canadian broadcaster Pierre Berton recorded many hours of autobiographical television interview for the Canadian Broadcasting Corporation, in Service's Monte Carlo flat. At this occasion, Service recited The Shooting of Dan McGrew and The Cremation of Sam McGee

Reviewing Service's Rhymes of a Rebel in 1952, Frye remarked that the book "interests me chiefly because ... I have noticed so much verse in exactly the same idiom, and I wonder how far Mr. Service's books may have influenced it. There was a time, fifty years ago," he added," when Robert W.Service represented, with some accuracy, the general level of poetic experience in Canada, as far as the popular reader was concerned.... there has been a prodigious, and, I should think, a permanent, change in public taste."

Margaret Rutherford recited most of "The Shooting of Dan McGrew" in the 1964 Ealing Studios film Murder Most Foul.

In 1968 Canadian-born country singer Hank Snow recorded recitations of eight of Service's longer poems for an album entitled Tales of the Yukon. The album was released by RCA Victor. Snow and other Musicians including Chet Atkins and Chubby Wise provided background music.

The Canadian whiskey Yukon Jack incorporated various excerpts of his writings in their ads in the 1970s, one of which was the first four lines of his poem, "The Men Who Don't Fit In".

After Service left for Europe, the Imperial Order of the Daughters of the Empire (I.O.D.E.) took care of the cabin until 1971, preserving it. In 1971 it was taken over by Parks Canada, which maintains it, including its sod roof, as a tourist attraction.

Irish-born actor Tom Byrne created The Robert Service Show which was presented in the front yard of the cabin, starting in 1976. This was very popular for summer visitors and set the standard for Robert Service recitations. A resurgence in sales of Service's works followed the institution of these performances. Byrne discontinued the show at the cabin in 1995, moving it to a Front Street storefront. Since 2004 the show has been held at the Westmark Hotel in Dawson City during the summer months.

The town of Lancieux, where he used to come every summer, organized several recognitions to the memory of Robert W. Service. One of the streets of Lancieux has been called Robert Service Street. On July 13, 1990, a commemorative tablet was unveiled at the Lancieux Office du Tourisme by the daughter of the poet: Iris Service. An evening of celebration was organized afterwards with a dinner attended by many guests from Scotland and the Yukon. A few years later, on May 18, 2002 the school of Lancieux in Brittany took the name of "École Robert W. Service". Charlotte Service-Longépé the great granddaughter and the granddaughter of the poet attended the dedication ceremony and made a speech. Since 2000, the towns of Lancieux and Whitehorse are sister cities, due to Robert W. Service's life and work in both places.

In her 2006 biography, Under the Spell of the Yukon, Enid Mallory revealed that Service had fallen in love during this period. He was working as a "farm labourer and store clerk when he first met Constance MacLean at a dance in Duncan B.C., where she was visiting her uncle." MacLean lived in Vancouver, on the mainland, so he courted her by mail. Though he was smitten, "MacLean was looking for a man of education and means to support her" so was not that interested. To please her, he took courses at McGill University's Victoria College, but failed.

In his E. J. Pratt lecture "Silence In the Sea," critic Northrop Frye argued that Service's verse was not "serious poetry," but something else he called "popular poetry": "the idioms of popular and serious poetry remain inexorably distinct." Popular poems, he thought, "preserve a surface of explicit statement" – either being "proverbial, like Kipling's 'If' or Longfellow's 'Song of Life' or Burns's 'For A' That'," or dealing in "conventionally poetic themes, like the pastoral themes of James Whitcomb Riley, or the adventurous themes of Robert Service."

Other verses quickly followed. "In the early spring he stood above the heights of Miles Canyon ... the line 'I have gazed on naked grandeur where there’s nothing else to gaze on' came into his mind and again he hammered out a complete poem, "The Call of the Wild". Conversations with locals led Service to write about things he had not seen (some of which had not actually happened) as well. He did not set foot in Dawson City until 1908, arriving in the Klondike ten years after the Gold Rush when his renown as a Writer was already established.