CLEVELAND — Cliff Pinkney, Cuyahoga County's first African-American sheriff, submitted a letter of resignation on Friday. 

Cuyahoga County Director of Communications Mary Louise Madigan told WKYC that Pinkney was departing for 'personal reasons.' "We thank him for his service," Madigan said. The county will release Pinkney's resignation letter on Tuesday. 

Madigan says search for a new sheriff will begin immediately. 

Pinkney was a 28-year veteran of the department and became sheriff in 2015.

He started as a deputy in 1991, then was promoted to detective two years later. In 1998, Pinkney joined the Narcotics Bureau. He then served on an FBI Task Force dealing with gangs, drugs and wiretaps. He became a sergeant in 2005 and oversaw the Sex Offender Unit in 2007.

Pinkney graduated from the FBI National Academy in 2012. He has won multiple honors for his job performance.