The diminutive Arano made his Liga debut for Poza Rica in 1959, going 8-9 with the Petroleros with a 4.47 ERA. He spent the next three seasons with Veracruz, including a disastrous 1960 campaign in which he was mainly used out of the bullpen and lost all five of his decisions with a sky-high 6.53 ERA. Arano turned things around in 1961, turning in an 11-3 record to lead the LMB in winning percentage for the pennant-winning Aguilas. He then reeled off 46 wins over the next three campaigns while making his only journey to play pro ball north of the border at the end of the 1962 campaign with Oklahoma City of the American Association, where he was 1-1 with a 9.82 ERA in three appearances.
After a mediocre 9-8 season with the Mexico City Diablos Rojos in 1965, Arano went on another three-year skein of effective pitching between 1966 and 1968, showing a 48-32 record with 400 strikeouts and a sub-3.00 ERA each season. An injury-shortened 1969 saw him go 5-7 before yet another three-year run of double-digit victories despite pitching for three teams (the Diablos, Saltillo and Cordoba) in that span.After suffering another shortened year with the Cafeteros in 1973 in which he was 6-4 with a career-best 1.66 ERA in ten starts, Arano went on an eight-year tear of solid pitching. Between 1974 and 1981, he won between 12 and 19 games every season while consistently registering sub-3.00 ERAs. After managing Cordoba for part of 1977 (they finished 86-64, but Arano was replaced by Wilfredo Calvino during the season), he won 19 games in both 1978 and 1979. He spent the strike-split 1980 season with Reynosa and won 14 games for the Broncos and turned in a 14-5 mark for the Diablos Rojos in 1981. Arano bounced around a bit after that, although he did go 11-9 for Veracruz as a 44-year-old in 1984.
He retired in 1986 before coming back in 1995 with the Aguilas, throwing one game in 1998 with Cordoba, and finally made one three-inning appearance in 2001 while he was a 62-year-old pitching coach for Veracruz. In all, Arano played in a total of 32 seasons (a Mexican League record) with eight teams.
He also played winter ball in the Mexican Pacific League for 15 seasons, compiling a decent 89-84 record with a solid 2.81 ERA with a no-hitter. Among his career highlights, Arano shut out Cleveland 4-0 in a 1967 exhibition game, but he saved the best for the following year. In a game in Mexico City, Arano beat Jim Bouton and the New York Yankees, 5-3, striking out Mickey Mantle twice.