Oswaldo Ochoa was met by cheers and applause from crowds of supporters on his arrival in Guatemala City.
Mr Ochoa, who said he had been inspired by Gandhi, wants social, political and agricultural change.
A series of corruption scandals forced the resignation of Vice President Roxana Baldetti last month.
Wearing a straw hat and a Guatemalan flag around his neck like a cape, Mr Ochoa, known as "Quixote", left his home city of Quetzaltenango a week ago.
He said he was joining a growing movement of Guatemalans who have been demanding the resignation of President Otto Perez Molina.
Mr Ochoa was on hunger strike during his journey, only drinking tea and juices. He got blisters on his feet and said he lost more than 4kg (9lbs) in weight.
In the capital, he called on all Guatemalans to rise against impunity and allegedly corrupt politicians who have enriched themselves with public money.
President Perez Molina, who has the backing of the army, says he has done nothing wrong and will not leave office before his term expires next January.
A 62-year-old man in Guatemala has received a hero's welcome after a 200km (125-mile) march in protest against government corruption.