He came from a very old Czech theatrical family of Steimar and artistic family of Kodet, he was the son of Czech actress Jiřina Steimar and sculptor Jan Kodet. After her parents divorced, her mother married Jaroslav Juhan, a car racer, but he emigrated. This had an impact on the further studies of Jiří Kodet, who was expelled from the grammar school and was not admitted to the DAMU until the second time.
He left the DAMU before graduating and began his theatre career at the East Bohemian Theatre in Pardubice (1961-1962). In 1962-64 he was in the Artistic Military Ensemble, based in Pohořelec, Prague. With this ensemble he toured a large part of the former Czechoslovakia. His future colleagues from the Drama Club, Jiří Hrzán, Jiří Zahajský and Petr Skoumal, were in the ensemble with him. In Pardubice, he was sought out by Jan Kačer, who was assembling a troupe for the Petr Bezruč Theatre in Ostrava. Kodet worked in Ostrava from 1963-1965, and from 1966 he played at the Prague Drama Club, where some of the members of the Ostrava ensemble moved. In 1991 he became a member of the drama company of the National Theatre in Prague.
During his lifetime he played a number of small and episodic roles in film and television, but it was not until the end of his life that he was able to play major roles, mainly thanks to director Jan Hřebejk, who cast him in his film Divided We Fall, and earlier also in Cosy Dens, which was his most successful film ever.
| 2003 | Sentiment |
| 2000 | Musíme si pomáhat as Dr. Fischer-Rybáf |
| 1999 | Pelíšky as Otec Kraus |
| 1994 | Akumulátor 1 as Mikulík |
| 1994 | Lepší pán |
| 1991 | Sbohem, Sokrate as Žak |
| 1990 | Evžen mezi námi |
| 1989 | Vážení přátelé, ano as Římský |
| 1989 | Hrobničky as Gentleman |
| 1989 | Kainovo znamení |
| 1989 | Smrt v kruhu as inspektor Vrba |
| 1988 | Pan Tau – der Film |
| 1988 | Jak básníkům chutná život as režisér Pergl |
| 1988 | Šašek a královna as King |
| 1988 | Operace mé dcery |
| 1988 | Dvě z Paříže |
| 1987 | Veselé Vánoce přejí chobotnice as Fára |
| 1987 | Papilio |
| 1986 | Růžový Hubert as Artur Harper |
| 1986 | Eine zauberhafte Erbschaft as Vévoda |
| 1986 | Velká filmová loupež |
| 1986 | Zátah |
| 1985 | Jestli jednou odejdu |
| 1985 | Ing. |
| 1985 | Rozpuštěný a vypuštěný as Továrník Bierhanzl |
| 1984 | Svatební cesta do Jiljí as Radovan |
| 1984 | Žofka z Janovic as Lieutenant |
| 1984 | Zaspala nevěsta as Milda |
| 1984 | Evo, vdej se! |
| 1984 | Byt je vykraden, maminko... |
| 1984 | Anděl s ďáblem v těle |
| 1984 | Modré z nebe |
| 1984 | Bergman a Bergman, detektivní kancelář |
| 1983 | Jen se spolehni |
| 1983 | Síť na bludičku |
| 1983 | Putování Jana Amose |
| 1983 | Duch soudce Pauknera |
| 1983 | Srdečný pozdrav ze zeměkoule |
| 1983 | Plášť Marie Terezie |
| 1983 | Smrt talentovaného ševce as Kapitán Michal Exner |
| 1983 | Smeč |
| 1983 | V hlavní roli obhájce |
| 1983 | Hráči as Utěšitel |
| 1982 | Jak svět přichází o básníky |
| 1982 | Skleněný dům |
| 1982 | Romance ze Savoy baru |
| 1982 | Plaché příběhy as (segment "Modrá chryzantéma") |
| 1981 | Panelstory aneb Jak se rodí sídliště |
| 1981 | Sobota odpoledne, počátek léta |
| 1981 | Tři v tom as Ubaldo |
| 1981 | Drž se rovně, Kačenko |
| 1981 | Fénix as Miro Hubej |
| 1981 | Buldoci a třešně as Giulio Salvatore |
| 1981 | Cukrová bouda as František Přibyl, otec Ondry a Martina |
| 1981 | Rána pod pás |
| 1981 | Jen si tak trochu písknout |
| 1981 | Dívka s mušlí |
| 1981 | A na konci je začátek |
| 1981 | Vrchní, prchni as Rudy |
| 1980 | Děti zítřků |
| 1980 | V hlavní roli Oldřich Nový |
| 1980 | Signum laudis as Kostolány |
| 1980 | Útěky domů |
| 1980 | Blues pro EFB |
| 1980 | Julek |
| 1980 | Pátek není svátek |
| 1980 | Modrá planeta as Petr Málek |
| 1980 | More v kvapke vody |
| 1979 | Od zítřka nečaruji |
| 1979 | Tajemství Ocelového města |
| 1979 | Pumpaři od Zlaté podkovy |
| 1979 | Bratři Kipové |
| 1978 | Past na kachnu |
| 1978 | Hrozba |
| 1978 | Poplach v oblacích |
| 1978 | Zlaté rybky |
| 1978 | Hra o jablko as MUDr. ArnoŠt Rýdl |
| 1977 | Noc klavíristy |
| 1977 | Osvobození Prahy |
| 1977 | Dům Na poříčí |
| 1976 | Město nic neví |
| 1975 | Sarajevski atentat as Morsley |
| 1975 | Ten kůň musí pryč |
| 1975 | Můj brácha má prima bráchu as herec v reklamním filmu |
| 1975 | Sokolovo |
| 1975 | Zbraně pro Prahu as nadporučík Sauer |
| 1974 | Egyptologové |
| 1974 | Zatykač na královnu |
| 1974 | Milenci v roce jedna as Assistant |
| 1973 | Rodeo |
| 1972 | Morgiana as Bessant |
| 1972 | Lekce |
| 1971 | Šance |
| 1971 | Kamarádi |
| 1971 | Revizor |
| 1970 | Velká neznámá |
| 1969 | Všichni dobří rodáci |
| 1968 | Klec pro dva |
| 1968 | Dita Saxová as Younger Werli's Son (voice) |
| 1967 | Hotel pro cizince as Jiří |
| 1967 | Lacrimae Rerum |
| 1966 | Sıkı Kontrol Edilen Trenler |
| 1966 | Zločin v dívčí škole as Pavel Lavecký (segment "Zločin v dívčí škole") |
| 1965 | Atentát |
| 1964 | Krysař |
| 1964 | Záhadný pan Hyde |
| 1963 | O něčem jiném as Jirka |
| 1962 | Kolik slov stačí lásce? as Mirek |
| 1961 | Pochodně as editor Norbert Zoula |
| 1960 | Lidé jako ty |
| 1960 | Vyšší princip |
| 1960 | Romeo, Julie a tma |
| 1960 | Probuzení as automechanik Emil |
| 1959 | Hlavní výhra |
| 1951 | Posel úsvitu |
Duvar