The Treasury imposed sanctions on Sechin in April 2014 as part of measures to pressure Russia over its intervention in Ukraine, saying Sechin had shown "utter loyalty" to Russian President Vladimir Putin.
The sanctions prohibit U.S. citizens or people in the United States from dealing with those on the blacklist, such as Sechin.
Tillerson left Exxon late last year to become secretary of state after 10 years running the company.
The back-and-forth between the Treasury and Exxon over the 2014 dealings spanned both the Obama and Trump administrations, and started with a subpoena from OFAC to Exxon in July 2014, Exxon said in its complaint.
Exxon has long opposed U.S. sanctions on Russia, saying they harm American business interests and actually help European rivals.
Tillerson said in 2014 that the company did not support sanctions because they are not effective "unless they are very well implemented.".
He also said that Exxon "never directly lobbied against sanctions," a claim that was immediately challenged by senators who cited Exxon's own lobbying disclosure forms. »