The flag simply replaces the celestial globe of the Brazilian flag with the state's coat of arms.
Article 2 of law no. 8889 of 31 August 1967 says, "the following proportions will be used for the flag: the height will be 14 units; the length 20 units; the vertices of the lozenge will be 1.7 units from the sides of the rectangle; the radius of the circle will be 3.5 units; the distance from the upper and lower edges of the arms to the edge of the circle will be 1 unit and that from the sides of the arms to the edge of the circle 2 units.
The flag was adopted on 25 August 1922 by the president of the State of Ceará, Justiniano do Serpa, being based on the flag of Brazil but substituting the state shield for the emblem on the center. The shield had been adopted on 22 September 1897 by Ceará state president Antônio Nogueira Pinto Acioli. In 1967 the legislative assembly approved the modification of the state shield in the center of the flag.
According to the state secretariat of culture, the flag was created by the prominent businessman João Tibúrcio Albano. It was his custom to fly the flag of his wife's home state of Maranhão at his estate, but, when he decided to hoist that of his own state of Ceará as well, he learned that one did not exist. He adapted the state coat of arms to the Brazilian flag, minus the starry blue globe and the motto Ordem e Progresso. This design served as a model for others used in the state, particularly flying from schools on public holidays, but only in 1922 did it become official.
According to Arthur Luponi, "The Flags of the States of Brazil: Ceará," Flag Bulletin 14:53-56 (Mar-Apr 1975), the 1922 flag of Ceará differed from the current one in having the points of the lozenge extend to the edges of the flag, as on the Brazilian imperial flag, and in the rendering of the coat of arms, which had been adopted in 1897 but was slightly modified in 1967. In particular, the flanking branches of coffee and cotton were eliminated. Both Luponi and Clóvis Ribeiro (1933), p. 160, state that the number of stars on the shield varied, although they were supposed to represent the municipalities of the state. The 1922 law adopting the coat of arms simply said the lower half of the shield was "sown [semeada] with stars symbolizing the different municipalities." In addition, Luponi notes that the colors of the coat of arms were previously unspecified and that some flags showed the dexter half as yellow with white stars, or green with gold stars and gold edging. The image above follows Ribeiro in having 25 stars and a narrow green fimbriation separating the white circle from the yellow lozenge. Like other state flags, that of Ceará along with the coat of arms was abolished under the Vargas constitution of November 10, 1937. Both were reinstated in their previous form by the new state constitution of 23 June 1947.