[3] In his youth, Loop was also interested in athletics, particularly boxing, and began training and competing in matches in his early teens.

[5] In the late 1950s, he also performed with the Tallinn-based ensemble Sinilind and the jazz group Metronoom, which included Uno Naissoo and other notable singers, composers, and musicians such as Kalju Terasmaa, Eri Klas, Tiit Varts, and Hillar Kareva.

[5] During the 1960s, Loop became a popular soloist singer, performing Estonian language light pop, jazz, and estrada music, and was frequently seen on Eesti Televisioon (ETV).

[7] One of his first hits of the era was the 1963 Arne Oit-composed and Heldur Karmo-penned song "Lõke preerias", which has since been covered by several Estonian artists.

[7] In 1964, Uno Loop wrote the first Estonian language guitar textbook, Kitarrimängu õpik, published by Eesti Riiklik Kirjastus and illustrated by Olev Subbi.

Other popular songs from his repertoire include: "Korraks vaid", "Isad ja pojad", "Kamina ees", "Väike neiu", "Ära koo mu käpikuisse päikest", "Vana klaver", "Oled teinud mind õnnelikuks", "Suudlused soolaste huultega", "Sinilind", and "Päiksepoolsel tänaval".

[2] Throughout his career, he has performed with and recorded music with a number of prominent musicians and singers, including Voldemar Kuslap, Ivo Linna, Jaak Joala, Kalmer Tennosaar, Els Himma, Vally Ojavere, Heli Lääts, and Ülle Toming.

[2] In 1961, Loop garnered his first acting role as Paul in the Viktor Nevežin-directed Tallinna Kinostuudio (now, Tallinnfilm) musical comedy Juhuslik kohtumine, starring Georg Ots and Lia Laats.

[9] In 1969, he appeared in the Tõnis Kask-directed Russian language drama film Chyornyy, kak ya, based on the 1961 book Black Like Me by American journalist John Howard Griffin.

Notable attendees included Prime Minister of Estonia Kaja Kallas, as well as singers and musicians Ivo Linna, Katrin Karisma, Urmas Lattikas, Erich Krieger, Jaan Elgula, and Tanel Padar.