In 2010, Shankland won the US Junior Championships which qualified him for the US Championship the following year. He took third place in that 2011 Championship, and then went on to achieve the biggest upset at the FIDE World Cup later that year by defeating Super-GM Peter Leko. Two years later, Shankland was part of the US National Team that won the Pan-American Championship that year, where he had a performance rating over 2800. He then received the 27th Samford Chess Fellowship, later that year.
In 2014, Shankland became one of the top 100 players in the world. He also won a gold medal at the 41st Olympiad for best reserve board player. He was undefeated ending with a score of 9 out of 10 in that Olympiad. He also defeated GM Judit Polgar in her last ever rated game during that tournament. Due to that performance, he played board one in the World Team Championship 2015, taking down some of the top fifteen players in the world at the time. In 2018, Sam Shankland had a stellar performance at the U.S. Championships. He won the tournament with 8.5/11 and crossed the 2700 barrier for the first time.