Eduardo Idar, journalist and civil-rights activist, was born in Laredo, Texas, on July 27, 1887, to Jovita (Vivero) and Nicasio Idar. He was at least a third generation Tejano. He married Irene Guerra in 1917, and they had three children, including Ed Idar, Jr,, who served as executive secretary of the American G.I. Forum. Idar attended eight years of school in Laredo (probably a combination of the public school and a private Mexican school) but was largely self-educated. He was proficient in both Spanish and English. From 1897 to 1902 he worked as a printing apprentice and at a print shop, probably his father's. In 1911–12 he worked for the San Benito Light and in 1912–13 for the Brownsville Herald. He was also active with the family newspaper La Crónica from 1911 to 1914. When Nicasio Idar died in 1914, the family moved to San Antonio, but Eduardo remained in Laredo. From 1913 to 1916 he was an auditor.
On January 22, 1917, he established the newspaper Evolución in Laredo. The paper circulated in Texas, Mexico, Cuba, and other Latin-American countries. It reported on the Mexican Revolution and supported United States entry into World War I and the participation of Mexican-descent servicemen in that war. It also advocated women's rights. In conjunction with the paper, Idar established Compañía Publicista Idar to do printing jobs and maintained a bookstore that sold books on history, science, literature, religion, pedagogy, medicine, languages, and Freemasonry (Idar was an avid Mason).
He devoted his life to journalism and educating Mexican Americans. In 1926 he began publishing another newspaper, Las Noticias, which had a circulation of 2,000 and was one of the best Spanish-language newspapers in Texas. In 1917 he had written that the Mexican press in Texas should initiate an active campaign of public instruction among its readers, and in 1927 he volunteered to take charge of Spanish-language propaganda for the movement to unite Mexican Americans into what eventually became the League of United Latin American Citizens. He was a speaker at the Harlingen Convention, where he argued against the inclusion of Mexicans in the organization. Idar became president of the Laredo chapter of the Latin American Citizens League, a South Texas civil-rights association. He served on the commission designated to study the constitution of the Orden Hijos de America (the Order of Sons of America) to further unification efforts among this group, the Latin American Citizens League, and the Order of Knights of America. He also tried to bridge differences between Alonso S. Perales and Santiago Tafolla, Sr. According to José T. Canales, Idar wrote most of the twenty-five aims and principles in the original 1929 LULAC constitution. Idar was a member of the constitutional committee and spoke at the LULAC constitutional convention in May 1929. He also wrote the LULAC code, a moral guide for members.
In the 1930s he became more directly involved in local politics. In 1932 he worked with the Progressive party, known among the Spanish-speaking community as the Partido de las Garras, and wrote and printed its broadsides. He ran for the office of county tax assessor, but he and his party lost. Due to the Great Depression and the costly bid for office, his business folded around 1932. He then moved to Falfurrias, where he continued to work in the printing business. In 1933, as the result of a political deal, he was awarded the position of deputy tax collector for Webb County, which he held until 1941. After that he worked on the staff of La Prensa in San Antonio for a short while. He died of a heart attack resulting from diabetes on March 13, 1947. Copies of Evolución are located in the Barker Texas History Center at the University of Texas at Austin.