Without quoting directly from the text give me a summary of Cesar Chavez greatest achievements.

Cesar Chavez (born Cesario Estrada Chavez /ˈtʃɑːvɛz/; Spanish: [ˈt͡ʃaβes]; March 31, 1927 – April 23, 1993) was an American labor leader and civil rights activist. Along with Dolores Huerta, he co-founded the National Farm Workers Association (NFWA), which later merged with the Agricultural Workers Organizing Committee (AWOC) to become the United Farm Workers (UFW) labor union. Ideologically, his world-view combined leftist politics with Catholic social teachings.

Born in Yuma, Arizona to a Mexican American family, Chavez began his working life as a manual laborer before spending two years in the United States Navy. Relocating to California, where he married, he got involved in the Community Service Organization (CSO), through which he helped laborers register to vote. In 1959, he became the CSO's national director, a position based in Los Angeles. In 1962, he left the CSO to co-found the NFWA, based in Delano, California, through which he launched an insurance scheme, a credit union, and the El Malcriado newspaper for farmworkers. Later that decade he began organizing strikes among farmworkers, most notably the successful Delano grape strike of 1965–1970. Amid the grape strike his NFWA merged with Larry Itliong's AWOC to form the UFW in 1967. Influenced by the Indian independence leader Mahatma Gandhi, Chavez emphasized direct but nonviolent tactics, including pickets and boycotts, to pressure farm owners into granting strikers' demands. He imbued his campaigns with Roman Catholic symbolism, including public processions, masses, and fasts. He received much support from labor and leftist groups but was monitored by the Federal Bureau of Investigation (FBI).

In the early 1970s, Chavez sought to expand the UFW's influence outside California by opening branches in other U.S. states. Viewing illegal immigrants as a major source of strike-breakers, he also pushed a campaign against illegal immigration into the U.S., which generated violence along the U.S.-Mexico border and caused schisms with many of the UFW's allies. Interested in co-operatives as a form of organization, he established a remote commune at Keene. His increased isolation and emphasis on unrelenting campaigning alienated many California farmworkers who had previously supported him and by 1973 the UFW had lost most of the contracts and membership it won during the late 1960s. His alliance with California Governor Jerry Brown helped ensure the passing of the California Agricultural Labor Relations Act of 1975, although the UFW's campaign to get its measures enshrined in California's constitution failed. Influenced by the Synanon religious organization, Chavez re-emphasized communal living and purged perceived opponents. Membership of the UFW dwindled in the 1980s, with Chavez refocusing on anti-pesticide campaigns and moving into real-estate development, generating controversy for his use of non-unionized laborers.

A controversial figure, UFW critics raised concerns about Chavez's autocratic control of the union, the purges of those he deemed disloyal, and the personality cult built around him, while farm-owners considered him a communist subversive. He became an icon for organized labor and leftist groups in the U.S. and posthumously became a "folk saint" among Mexican Americans. His birthday is a federal commemorative holiday in several U.S. states, while many places are named after him, and in 1994 he posthumously received the Presidential Medal of Freedom.

Cesar Chavez is widely regarded as the folk hero fighting for the rights of farm workers in the 1960's and 1970's. He is the co-founder of the farm workers union and helped to pass laws in California protecting farm workers. He worked on expanding the movement throughout the United States but had limited success.