Leeser was born in Mexico and immigrated to the United States with his family at the age of 9, living in Sun City and then afterwards settling in El Paso, Texas. He started his first job at 16. Following graduation from Coronado High School in El Paso, Leeser began his career in the auto industry, working with several dealerships in El Paso. Leeser was given a career opportunity in 2001, when he became president and dealer operator of Hyundai of El Paso. He had turned a local store that was only selling 15 cars a month into the number one overall dealer in El Paso. His store also became the number one Hyundai dealer in the SouthCentral Region and ninth in the United States for Hyundai dealers. He amassed over three decades of experience in business, culminating in his service as owner and president of Hyundai of El Paso before becoming mayor.
Community work
Leeser serves as a member of the UMC El Paso Children's Hospital Foundation Board and also holds several professional positions as well. He is the President of the Hyundai South Central Region, a member of the National Dealer Council, serves on the National Parts and Service Committee, and the Hyundai Advertising Committee. In addition, he has also been active in supporting many local charities and youth organizations.
Leeser was elected mayor on May 14, 2013 after defeating city council member Steve Ortega. Both Leeser and Ortega ran as nonpartisan candidates as the city of El Paso only holds nonpartisan elections. Ortega had placed first and second with 47% and 21% of the vote, respectively, and because no candidate received a majority, a runoff election was held on June 15 which Leeser won. He took office on June 24, 2013.
2017 election
Mayor Oscar Leeser was eligible to run for a second term in office, but announced in July 2016 that he would not seek another term. Many had thought it was due to the fact that Leeser had a cancer related surgery in 2016, but stated that his decision is not because of his health. Instead, it is because he "ran to do things I thought were really important for our community and I did that." Leeser was succeeded by RepublicanDee Margo, whom he endorsed in the runoff election.