Barack Obama served as the 44th President of the United States from 2009 to 2017, making history as the first African American to hold the office. He is known for his efforts in healthcare reform, notably the Affordable Care Act, and for his focus on climate change and renewable energy. Before his presidency, Obama was a U.S. Senator from Illinois and a community organizer. His leadership style emphasized diplomacy and collaboration, both domestically and internationally. After leaving office, he continues to be an influential figure through his foundation and public speaking engagements.