He graduated in history and library studies from the Faculty of Humanities of the Eötvös Loránd University in Budapest in 1977, and in 1980 he received his doctoral diploma in humanities.
Gyimesi served as Mayor of Zalaegerszeg from 1994 to 2010. Since 1977 he has been an assistant to the county library in Zalaegerszeg researching local history. From 1981 he was director of József Attila Library, from 1986 deputy director, and from 1988 until 1994 director of the county archives.
Since 1972 he has been the author of several studies on local history and cultural history as well as individual publications, and editor of the journal Zalai Gyűjtemény (Zala Collection).
He was chairman of the basketball section of the sports club ZTE Goldsun from 1992 to 1994. He has been the chairman of Degré Alajos Foundation for Ethnography since 1992 and chairman of Millecentennial Foundation since 1996.
Since 1997 he has been on the Hungarian Olympic Committee. He received ministerial recognition several times and the was conferred upon him by the Minister of Economy in 2001.
Political career From December of the same year he was chairman and since 2000 he has been deputy chairman of the Cultural Committee of the Alliance of Cities with County Status.
On 20 October 2002 he was elected mayor for the second time. On 21 April 2002 he was elected individual representative for Constituency I (Zalaegerszeg), Zala County. In the autumn of 2003, at the beginning of the party"s restructuring into a people"s party he was charged with heading the Zalaegerszeg constituency.
He was elected Member of Parliament from the Zala County Constituency I in the 2006 and 2010 elections.
With support from the Hungarian Democratic Forum (Magyar Demokrata Forum (Hungarian Democratic Forum)), the Christian Democratic People"s Party (Keresztéugdemokrata Néppart (Christian Democratic People's Party)), Fidesz and the Independent Smallholders" Party (FKGP), he was elected Mayor of Zalaegerszeg on 11 December 1994 and re-elected in October 1998 with the support of Fidesz, the Hungarian Democratic Forum (Magyar Demokrata Forum (Hungarian Democratic Forum)), the Hungarian Christian Democratic Alliance (MKDSZ) and the Christian Democratic People"s Party (Keresztéugdemokrata Néppart (Christian Democratic People's Party)). In the 1998 parliamentary elections he was a candidate of Fidesz. He joined Fidesz - Hungarian Civic Party (Fiatal Demokratâk Szovetsége (Federation of Young Democrats)-Master in Public Policy) in 1999.
He was president of the Alliance of Zala County Civil Organisations from 1990 to 1995, and a member of its National Board. He was invited to, and became a member of, the County General Assembly in 1991. In October 1998 he was elected member of the Zala County Assembly.
Since the beginning of the term he had been member of the Local Government Committee.
He was member of the Parliamentary Committee on Culture and the Media.