He played in Major League Baseball (MLB) for the Pittsburgh Pirates, Florida Marlins, New York Mets, and Baltimore Orioles.

Paulino signed as a non-drafted free agent with the Pittsburgh Pirates organization on December 29, 1997, at the age of 16.

In 2002, he was selected by the Kansas City Royals in the Rule 5 draft, but he was returned to the Pirates in spring training of the following year.

After making his major league debut in September 2005 with the Pirates, Paulino was selected to the Dominican Republic team for the 2006 World Baseball Classic as a backup catcher.

Eventually he was again demoted to the Triple-A Indianapolis Indians, as management would give Ryan Doumit the bulk of playing time behind the plate with the Pittsburgh Pirates.

[2] On December 10, 2008, Paulino was traded to the Philadelphia Phillies in exchange for minor league catcher Jason Jaramillo.

[7] With the news of the death of Osama bin Laden, the al-Qaeda leader who was the mastermind of the September 11 attacks circulating during the game against their rivals, Mets manager Terry Collins said that Paulino delivered "a good win for us, and obviously a huge win for America tonight.

[10] Paulino made the Orioles' 2012 Opening Day roster after Taylor Teagarden, newly signed by the team to be the backup catcher, went on the disabled list due to back problems.

[12] On July 15, Paulino was optioned to the Triple-A Norfolk Tides to make room for Teagarden, who was coming off from the 60-day disabled list.

On August 13, 2013, the Orioles assigned Paulino to the Toledo Mud Hens, the Detroit Tigers Triple-A affiliate.