Foster played two years at Pearl River Community College during 2009 and 2010. He then transferred to the University of West Alabama where he completed his college career in 2011 and 2012, where his career record included 96 tackles, 16 pass deflections and 10 interceptions.
Professional career
Kansas City Chiefs
In May 2013, Foster signed with the Kansas City Chiefs of the NFL, as an undrafted free agent He played three preseason games with the Chiefs before being cut from the team.
Toronto Argonauts
He then moved to the Canadian Football League, signing with the Toronto Argonauts from whom he was acquired by the Edmonton Eskimos in 2014. He was traded to Edmonton from Toronto on May 13, 2014 along with Toronto's first and second round picks in the 2014 CFL Canadian Draft, import offensive lineman Tony Washington and a negotiation list player, in exchange for Edmonton's first and third round picks in the 2014 CFL Canadian Draft and a negotiation list player.
Edmonton Eskimos
After being traded to the Eskimos Foster became an immediate starter, and played in 16 games in the 2014 season. Foster recorded 46 defensive tackles, five special teams tackles, five pass knockdowns, one interception, one sack, one fumble recovery and one forced fumble. In the Labour Day Classic, Foster recovered a blocked punt by Willie Jefferson and scored a 57-yard touchdown. In the West Semi-final against Saskatchewan, Foster recorded one defensive tackle. In the West Final against Calgary, he recorded two defensive tackles. Foster continued his strong play in the 2015 season, contributing 57 tackles, 2 special teams tackles, 2 sacks, 1 interception, 1 forced fumble and 1 defensive touchdown.
Saskatchewan Roughriders
On February 10, 2016, Foster signed as a free agent with the Saskatchewan Roughriders of the CFL. Foster had his best statistical season in 2016 playing in all 18 regular season games and racking up 71 tackles and 3 quarterback sacks. Set to become a free-agent in February 2017, Foster had a workout with the New Orleans Saints In December 2016. On January 20, 2017 Foster had a workout with the Baltimore Ravens. On January 27, 2017, a couple weeks before becoming a free agent, Foster was released by the Riders so he could pursue NFL opportunities.
Baltimore Ravens
On January 31, 2017, Foster signed a reserve/future contract with the Baltimore Ravens. He was waived on September 1, 2017 during final roster cutdowns.
Saskatchewan Roughriders
He signed with Saskatchewan in September 2017.
BC Lions
Foster signed with the BC Lions on February 14, 2018.
Personal life
Foster joined the United States Marine Corps in 2007 after he was redshirted at Southern University, attending basic training at Marine Corps Recruit Depot Parris Island and becoming a communications expert. He served in the Marines while playing football for two years at Pearl River Community College. He is the father of one daughter, Olavia K. Foster, born on April 16, 2010. Foster's Mother is Valerie Lee Foster Aikens. Foster's father, Otha Foster Jr., died January 9, 2010 after being a disabled dialysis patient for 19 years. Foster III was the main caregiver for his father since the age of eight. Even though Foster Jr. was on dialysis, he still managed to coach Foster III's little league football team. He lived to see him play JUCO, but he died at the age of 43, during Christmas break, before Foster III started at West Alabama. Otha's Mother is Valerie J.Lee-Aikens and his stepfather is Steven L. Aikens. Otha III's parents, Otha Jr. and Valerie separated when Otha III was 3 years old and later divorced. Otha has three sisters Clara Lopez, Tiffany Lee, Tiara Foster and one brother, Tyler Smith.