Born in Milan, Leonardo Gagliano started his career in the Victor Hugo Arias studio in 1972. He then worked at Studioriga between 1974 and 1982. For the studio he drew pocket serie 'Misterlady' (Furio Viano Editore, text Ghelardini, covers Graziano Origa); volumes 1-10 all alone and issues 11-27 with ink by Enea Riboldi. He drew pockets for Ediperiodici (for example 'Terror Blu', 'Scandali al Sole', 'Sex Alien', 'Storie Nere', 'Verità Segrete', 'Voglia Matta' and the thriller 'Ron Zeguvi' with Forte and Romanini) and Edifumetto ('Orror', 'Superproibita').
Gagliano drew free stories for Universo and Corrier Boy. In 1981 he started the serie 'Kostance Kash' inside the weekly mag Adamo (Editoriale Corno) and, for the same publisher, he succeeded Enrique Romero on a pocket created by Max Bunker, 'Cliff' (1979), using the pen name Enriquez de la Vega. He also made some stories of 'Apache' in Dallas Angels and in Morbosità with, Savi, Truscia, Zappa and covers by Marcarini (Edizioni Sud).
From 1983 he worked for the Gianni Bono agency at the Staff di if/Epierre ('Anna dai capelli rossi', 'Marshall Bravestarr'). In the late 1980s he drew 'Brave Starr' written by Sauro Pennacchioli. Since 1992, he has drawn many stories and covers for Disney Italia ('Topolino', 'Minnie', etc). He is additionally active for the advertising market. His brother Salvatore is also a comic artist ('Lady Inferno' in Calze Nere and 'Pussycat' at Eusebio Editore).