[4][5] Zinkevičius was a member of the editorial boards of the Lithuanian Language Society (Lietuvių kalbos draugija) and of the international periodicals "Baltistica [lt]" and "Lituanistica".

[6] Zinkevičius was fluent in a number of languages, including English, German, Russian, Polish, Ukrainian, Belarusian and French.

[8] Zinkevičius's academic career began in 1946,[1] when he held the position of chief laboratory assistant at the Lithuanian Department of Vilnius University until 1950.

[4] Zinkevičius was also the deputy dean of the Faculty of History and Philology in 1956–1968[8] and between 1962 and 1964, held the position of chief researcher.

[4] Between 1964 and 1966, together with Aleksas Stanislovas Girdenis [lt], Zinkevičius prepared a new classification of the dialects of the current Lithuanian language.

[5] In 1967, he defended his doctoral thesis Lietuvių dialektologija (Lyginamoji tarmių fonetika ir morfologija) ('Lithuanian Dialectology (Comparative Phonetics and Morphology of Dialects)').

[12][13] According to Polish historian Barbara Jundo-Kaliszewska, during the 1980s and 1990s, Zinkevičius was one of the prominent activists of the nationalist and anti-Polish,[14] organization Vilnija,[15] whose main goal was a rapid Lithuanization of the Vilnius region.

[1][18] During his tenure as Minister of Education and Science, he helped intensify the policy of Lithuanianization of the Polish minority living in Lithuania.

[19] On February 3, 2015, he was one of 60 signatories of an open letter addressed, among others, to Lithuanian President Dalia Grybauskaitė and members of the government, in which he demanded that the Polish minority party LLRA be excluded from the government coalition and that the party's deputies be stripped of their seats in the Seimas, due to the stated reasons that LLRA's views are openly directed against the state and it repeatedly lies in international forums about discrimination against the Polish minority in Lithuania, without specifying which parts of Lithuanian or international law were broken by Lithuania.

[20] On August 28, 2015, he published an open letter addressed to the Minister of Education Juozas Bernatonis protesting a planned reform allowing Poles in Lithuania to spell their names in Polish, arguing that: "Undoubtedly, the supposedly Polish surnames of most Polish-speakers in Southeastern Lithuania are actually of Lithuanian origin.

[21] After Zinkevičius's death, Lithuania's prime minister between 1996 and 1999 Gediminas Vagnorius said that Zinkevičius "brought a different approach, a sincere, matter-of-fact, professional approach to education policy and forced others to step up" and described him as "very sincere, very benevolent and distinguished by high intelligence".

[6][26] The contemporary president Dalia Grybauskaitė, when expressing her condolences on his death, said that Lithuania lost an outstanding linguist: The fundamental scientific works of the long-time Vilnius University professor made it possible to learn about the past of our language and nation, to understand its origin, to strengthen Lithuanianness and national self-esteem.

[4]Zinkevičius is highly acclaimed in international sources, where he is described as an "excellent linguistic historian of the greatest professional repute",[27] "eminent",[28] and "great Lithuanian scholar".

[10] The contemporary Minister of Education and Science Dainius Pavalkis [lt] emphasized that Zinkevičius's scientific work made Lithuania famous in the world and thanked Zinkevičius for his strengthening of the Lithuanian schools in southeastern Lithuania while he was a minister: "You achieved that all residents of this region who want to learn Lithuanian could do so.

"[10] Professor Romualdas Baltrušis [lt], Zinkevičius's childhood friend, recalled that the years of Soviet occupation was hard for Zinkevičius and was glad that his work remained serious, uninfluenced by the Communist ideology, and that he did not ignore the dangerous events for Lithuania and defended Lithuanian language and national identity from those opposed to them.

Pamilęs lietuvių kalbą ('Zigmas Zinkevičius: Having Fallen in Love with the Lithuanian Language') created by director Algirdas Tarvydas in 2015.

[1] For his services to Lithuania in 1995, Zinkevičius was awarded the Order of the Lithuanian Grand Duke Gediminas, 3rd Class.

[1] In 2015, on July 6, the Lithuanian Statehood Day, Zinkevičius was awarded the Commander's Grand Cross of the Order for Merits to Lithuania by president Grybauskaitė.

According to Weeks, Zinkevičius in his book Eastern Lithuania in the Past and Now (published in 1993) "wishes to argue for the eternal Lithuanian nature of the region, a viewpoint that no historical or linguistic methods seem likely to support.

[33] He emphasizes that Zinkevičius tends to ignore the actual ethnographic data and alleged national self-identification of the inhabitants, in favour of promoting the thesis of the unchanging Lithuanian nature of the region.

[33] Polish researcher Robert Boroch is of a similar opinion, in his review of Zinkevičius's work The History of the Lithuanian Language (published in 1996) Boroch emphasized that "the weakness of the work is the lack of objectivity, mixing ideology and scientific facts".

[5] In addition, Zinkevičius is also the author of the following books (this list is not comprehensive):[5] Zinkevičius has also published studies regarding the Lithuanian language in the writings of Martynas Mažvydas, Konstantinas Sirvydas, Mozerka Saliamonas Slavočinskis [lt], Kristijonas Donelaitis and the Wolfenbüttel postil.