Whilst studying in the Netherlands she was supported by Eesti Kultuurkapital. Rüütel won First Prize in the National Competition for Young Classical Singers in Estonia three years in a row in 2001, 2002 and 2003.
In 2009 Rüütel became a member of the prestigious Jette Parker Young Artists Programme at the Royal Opera House, Covent Garden, making her debut as Venerable Lady in The Gambler and covering the role of Blanche. Her roles for the company included Hansel Hansel and Gretel, Rosette Manon and Flora La traviata (also performed on tour in Japan), Second Lady Die Zauberflöte conducted by Sir Colin Davis, and Dorothée Cendrillon. She covered Madame Dangeville Adriana Lecouvreur, Charlotte Werther and Dunyasha The Tsar’s Bride.
Since leaving the programme she has returned to the Royal Opera House as Meg Page Falstaff in a new production by Robert Carsen, Wellgunde Der Ring des Nibelungen and as Marchesa Malibea Il Viaggio a Reims in a special gala performance. She also made her debut with Scottish Opera as Hansel in a new production of Hansel and Gretel. Recent concert and recital engagements include her US debut with the St Louis Symphony Orchestra singing Mozart’s Requiem; a hugely acclaimed debut performance of Elgar’s Dream of Gerontius for The Three Choirs Festival; Mahler Rückert Lieder at the Cadogan Hall; Beethoven Mass in C with City of Birmingham Symphony and Philharmonia orchestras; Zemlinsky’s Sechs Gasange at Philharmonie Berlin; and gala concerts in Latvia and the Czech Republic.
Last season she appeared as Blanche in a new production of The Gambler at De Nederlandse Opera, Sonyetka in a new production by Calixto Bieito of Lady Macbeth from the Mtsensk District at Vlaamse Opera and Siegrune Die Walküre at Gran Teatre del Liceu. On the concert platform she made her debuts with the Residentie Orchestra of the Netherlands singing Beethoven’s Symphony No.9 and with the RTE Orchestra and John Wilson in a special Opera Gala Concert.
In 2014/15 Kai Ruutel makes her debut at the Théâtre du Capitole de Toulouse as Kate Julian Owen Wingrave, and returns to Vlaamse Opera as Nefertiti in Glass’s Akhnaten and to the Royal Opera House as Meg Page Falstaff. She also makes her recital debut in Estonia, accompanied by Roger Vignoles. Further ahead she makes debuts with Teatro Real and Dallas Opera and returns for new prodcutions at Royal Opera House and Dutch National Opera.