After a year at the Conservatory, Auer launched his student, now age 17, with solo recitals in St. Petersburg and Helsinki. There were financial pressures for such an undertaking: "I remember when I was going to Berlin, Auer was very worried about my debut because it meant everything. We had practically no money, and when all expenses of concerts had been paid for[,] we had exactly ten pounds" (Hambleton, 1978). There followed concerts in Berlin and a tour of Norway, Germany and Holland in 1908, including the first of many appearances before King Haakon and Queen Maud of Norway. It was in Oslo that the Parlows met Einar Björnson, the wealthy Norwegian who became Kathleen's patron and close friend. It was from the generous Björnson that she received the priceless violin that enabled her to reach new heights. This violin, a Guarnerius del Gesù created in 1735, remained her primary instrument.
Minnie Parlow travelled with her daughter to each appearance and continued to do so long after her daughter reached adulthood. Leopold Auer, too, retained a strong influence on his former student, helping to arrange engagements and advising her on which pieces to perform and how to interpret them. The young musician accepted their involvement, as she accepted and even embraced the discipline necessitated by touring. Kathleen seems to have viewed her relationship with Auer as father-daughter as well as teacher-pupil; Kathleen studied with him whenever they could be in the same city and she nicknamed him "Papa Auer". (Auer, however, recalled Kathleen as only one of the 30 or 40 former students who frequently gathered at his music colony near Dresden.)
Together Auer, Mrs. Parlow and their agents planned Kathleen's concerts to display the young virtuoso to best advantage. Having studied and performed in Europe for five years, a period that included concerts with conductors Thomas Beecham and Bruno Walter, among others, the Parlows returned to North America in November 1910 for the obligatory tour. There, Kathleen performed in New York, Philadelphia, Montréal, Québec City, Ottawa and Kingston, and made her first of many appearances with the Toronto Symphony Orchestra in February 1911. In every venue, she was lauded as one of the highest-ranking violinists. The Parlows were especially gratified by Kathleen's acceptance in Western Canada, where she performed in Calgary, Regina, Moose Jaw, Saskatoon, Edmonton, Vancouver and Victoria, and was honoured by civic officials and provincial premiers.
Afterwards, they returned to New York for performances with the New York Symphony Orchestra; the critics were by then championing Parlow as the equal of her friend, the virtuoso Mischa Elman. "The gifts of this young girl are extraordinary.… In her performances she has not been judged as a woman but as an artist.… The profession have declared that she is today one of the phenomena of the musical world" (New York Herald, 1911).
There followed a return to England in June 1911, where the Parlows met with "Papa Auer" again to prepare for recitals Kathleen -- now a young woman of 21 -- was to give for the Ostend Festival. Her schedule remained heavy, and they crossed and re-crossed the Atlantic many times. They returned to North America for a second concert tour of Canada and the U.S.; in New York, she appeared at a benefit concert for the survivors of the Titanic. At this time, she also made her first recordings, at the request of Thomas Edison, in addition to recordings for the Columbia label. Parlow returned to St. Petersburg and Moscow in November 1912, for engagements arranged by Auer.
To this point, Parlow's repertoire comprised primarily solo works such as concerti. Now, however, she began to explore the chamber repertoire and with the Italian pianist, Ernesto Consolo, she gave her first sonata recitals at New York's Hotel Astor, in January 1912. She enjoyed the experience and began to feature chamber pieces in her repertoire; later, after she gave up solo touring, it was chamber music to which she turned to rejuvenate her career.
Kathleen and her mother purchased a country home in Meldreth, Cambridgeshire, England, to which they could retreat between engagements. Here, she also began to collect books; reading was a welcome escape from the demands of her career.
In 1914, Parlow undertook her third North American tour, during which she recorded several pieces (such as Rubinstein's "Melody in F") for Columbia Records. They had already returned to England when the First World War broke out. Despite the dangers of travelling during wartime, Kathleen toured the neutral nations of Holland, Denmark, Norway and Sweden. In August 1915, she met Auer to prepare more repertoires before leaving for North America in December. She spent the spring of 1916 touring the U.S. and Canada, and recording Dvorak's "Indian Lament" and other pieces. By 1917, she was back in England, but a travel ban reduced opportunities to earn concert fees and she was unable to recommence her arduous schedule until 1919.
By this time, Auer had been forced by the political situation in Russia to immigrate to New York, but his association with the Parlows had cooled. Perhaps Kathleen, now a seasoned professional, felt less need for her mentor's advice and encouragement.
In December 1920, the Parlows undertook Kathleen's fifth concert tour of the U.S. While there, she performed her first radio broadcast, from Seattle, in April 1922. From there she went on to Hawaii and a 22-month tour of the Far East and the Dutch East Indies, following in the footsteps of Éva Gauthier, who had toured there from 1911 to 1914. Parlow appeared on the stages of China, Java (Indonesia), Singapore and Korea. She also performed in Japan, where she was invited to record for the Nipponophone Company.
In the wake of this enormous success, the Parlows returned briefly to England and Kathleen continued to perform across Europe. However, despite a high profile in continental musical centres, she and her mother were disappointed that she did not enjoy similar prominence in England. There are also hints of a broken personal relationship, fatigue and perhaps a nervous breakdown around 1926 or 1927. The combination of pressures seems to have led to their decision to seek opportunities in North America. A year-long concert hiatus, about which little is known, coincided with their move.
Subsequently, in an attempt to resuscitate her career, Parlow agreed to perform a series of concerts in Mexico City in April 1929. For the first time, she travelled without her mother. In Mexico, Parlow was praised as superior even to Heifetz, but was never able to earn as much money as her contemporary. In fact, even after performing numerous extra concerts, she barely broke even after paying travel and hotel expenses and agents' and accompanists' fees. This may have been one of the experiences that she referred to when she later told an interviewer, "When things were very hard, we often thought -- mother and I -- why not give it up and get a job, do something that would bring in less fright for the future, but I knew I just couldn't do it" (Hambleton, 1978).