According to the Hillsborough County Sheriff's Office, authorities spoke with him as part of a welfare check just a few days ago.
Sheriff’s officials said his family initially reported Jackson missing on Wednesday. Deputies tracked him down to the hotel two days later, spoke with him, and canceled the missing persons case.
Sheriff Chad Chronister said his department has opened an investigation.
"My heart aches for the many loved ones Vincent Jackson leaves behind, from his wife and children to the Buccaneers nation that adored him," Chronister said in a statement posted on social media.
"Mr. Jackson was a devoted man who put his family and community above everything else," the sheriff said, noting that Jackson was made an honorary deputy.
Jackson, who played with former Chargers quarterback Philip Rivers, surpassed 1,000 receiving yards six times during his career and was a Pro Bowler in 2009 and 2011 with the Chargers, and in his first season with Tampa Bay in 2012.
Both the Chargers and Buccaneers put out statements regarding Jackson's contributions to each organization during his playing days.
Both of Jackson's parents served in the Army, and he told Fox News last May that it was "a big part" of his life, and "it really created the culture in the upbringing and the mindset" that he had. Jackson’s foundation, Jackson In Action 83, concentrated on providing support to military families, focusing on the educational, emotional, and physical health of the children.
The NFL world reacted to the news of Jackson’s death.
The Associated Press contributed to this report.