He is known for managing actors, being the manager for ABS-CBN's Star Magic (formerly the Talent Center), as well as the senior vice-president of ABS-CBN.
Manahan was born on February 11, 1947 in Quezon City, Philippines. His parents were Dr. Constantino Perez Manahan and Elvira Ledesma Manahan, who was also known for her television series, Two For The Road. Manahan attended high school in Ateneo de Manila in 1964, and finished his studies at the University of California, Berkeley, AB Art History, in 1969.
Before becoming the director-manager, Manahan was first became a visual artist, paintor, and sculptor. In fact, he received the "Special Citation" award at the Paris Beinnale of Art in 1979.
Manahan began his career directing for television soon after his studies around 1971. He was a freelancer and directed shows for the various local channels such as Two for the Road, For the Boys, The Big Big Show, and Kaluskos Musmos. Right after BBC-2 re-opened in 1986 and becomes the ABS-CBN Broadcasting Corporation, he was appointed as a resident director at the network. He is the director of the leading shows of the history of the local television, such as Chika Chika Chicks, Palibhasa Lalake, Tonight with Dick and Carmi, and Abangan Ang Susunod Na Kabanata.
In April 1992, Manahan, then program director, and Freddie Garcia, then ABS-CBN executive vice president and general manager, formed the idea of creating a stable of new stars exclusively for the network. This gave birth to Talent Center. In its early years, the Talent Center's project was Ang TV. The show auditioned thousands of people and accepted chosen ones into the program. The series soon led to mall shows, live concerts, and record albums. It also became a springboard for the careers of Claudine Barretto, Jolina Magdangal, Camille Prats, Victor Neri, and Paolo Contis among others. The Talent Center continued its search through the launching vehicle Star Circle in 1995.
While he is busy discovering and developing new talent, Manahan is still doing his directing duties for television shows, movies, concerts, and specials. In particular, he directs the first collaboration of Martin Nievera and Gary Valenciano's major concert in September 2009 at the Mall of Asia concert grounds, as well as foreign celebrities' Barry Manilow, Diana Krall, and Andrea Bocelli's concerts in the Philippines.
He is the man behind the Ms. Earth pageants, the Christmas and anniversary specials of ABS-CBN, celebrity weddings and debut specials, election specials, and many more. In addition, he also manages the grand world tours and concerts outside the country which includes ASAP '05 in USA and Japan, Wowowee in Las Vegas, Chicago, Hawaii, and more, Star Magic World Tour in Canada and USA, among others.
Throughout his career, Manahan's career expanded and he has held different positions in the network management. He had been the Director in the Talent Center (1992-1994); Program Director in the Production Department (1994-1996); and Vice President in the Talent Development & Management Center (1996-2003); Senior Vice President of ABS-CBN's Star Magic (2003-2007). In 2007, he stepped down from his position and retired in 2007, and stayed as the Head and Consultant of Star Magic.
Manahan was a mentor to a number of people who went on to become well-known in show business in the Philippines; among these are Star Magic include Piolo Pascual, Claudine Barretto, Angelica Panganiban, Diether Ocampo, Bea Alonzo, Kim Chiu, Gerald Anderson, John Lloyd Cruz.