Seilhamer was raised in Ponce, Puerto Rico, where he studied his elementary and high school at the Santa María Academy.

In 1976, Seilhamer received his bachelor's degree in civil engineering from the University of New Haven, graduating cum laude.

In 1979, he completed a second bachelor's degree in Science, with a concentration in Pre-medicine, from the University of Puerto Rico at Mayagüez.

When he was 17 years old, he also joined the Baloncesto Superior Nacional league, as a member of the Leones de Ponce.

[citation needed] In February 2007, Seilhamer decided to participate in the primaries of his party for the Senate of Puerto Rico.

[6] Seilhamer was elected to the Puerto Rico Senate on November 4, 2008, representing the District of Ponce.

In August, 2011, Seilhamer became Senate Majority Leader, after he was chosen to fill the vacancy left by Roberto Arango.

[13] Debora (born on 1985) played for the USC Trojans volleyball team of the University of Southern California.