In 1996 he became senior counsel for mergers & acquisitions for SBC Communications closing multiple deals worth several billion dollars in U.S., Europe, and South America as well as negotiating a strategic partnering agreement with a global internet service provider.
He has negotiated many hundreds of business disputes in favor of his clients, shepherded a company through bankruptcy in 56 days, and overseen the effort to gain temporary restraining orders in emergencies.
During the course of his time at Bryan Cave LLP and SBC Communications (now AT&T), Hartmann covered cases involving equal opportunity employment, personal injury and products liability, sexual discrimination, contract breaches and fraud, employment status and unemployment, international attachments, state wage-payment class action, government contract and bid protest disputes, as well as pension rights.
Over the course of his career as general counsel, Hartmann resolved several hundred critical litigation matters including workers' compensation, business and contract disputes, and class actions.
Apart from litigation, Hartmann also led successful arbitrations and mediations on multimillion-dollar matters as well as the effort to obtain two temporary restraining orders in N.Y. federal court to end a business-halting dispute.
Hartmann served on active duty (1977-1991 & 2007–2009) and in a reserve capacity (1991–2007) in the United States Air Force for 32 years, retiring as a brigadier general in December 2009.
He helped lead a special trial advocacy training program and was recognized with the Outstanding Judge Advocate award, Headquarters, Air Force Reserve, in 1993.
As legal advisor Hartmann oversaw investigation, proof analysis, charging, and inter-governmental coordination on cases involving conspiracy, murder, and war-related crimes.
If he believes in military commissions as strongly as I do then let's do the right thing and both of us walk away before we do more harm.The Wall Street Journal reported that Davis and Hartmann had clashed over which captives should face charges.
According to Jennifer Daskal, an attorney at Human Rights Watch:[6] It is totally outrageous that the prosecution would try to push ahead with a hearing on whether or not Khadr was an unlawful enemy combatant, while all the time withholding from the defence potentially exculpatory information.
[12][13] Henley had arranged for depositions to be taken from other officers at Guantanamo, including US Navy Captain Patrick M. McCarthy, who testified that Hartmann had personally berated him.
[12] In his August 14, 2008 ruling Henley wrote:[13] ... a Legal Advisor's post trial responsibilities necessitate he act in a quasi-judicial role; one where he must remain neutral and unbiased.
In testimony at a pre-trial hearing for Jawad on August 20, 2008 US Army Brigadier General Gregory Zanetti, deputy prison camps commander at Guantanamo, described Hartmann as, "abusive, bullying and unprofessional...pretty much across the board.
However Deputy Secretary of Defense Gordon England, the Pentagon's second highest official, was willing to comment, saying: Misunderstandings of the military commission process have led to confusion and controversy.
General Thomas Hartmann, found his file among those being considered for war crimes prosecution and propelled it to the top of the pile, in part because there were victims who could testify -- former, wounded reserve soldiers back in California.
"[19] On 2 November 2008 Carol Rosenberg, writing in the Miami Herald, reported that Hartmann had filed a request to retire from the Air Force on 17 February 2008.
[21] William Glaberson, writing in The New York Times, reported that Hartmann had been rehearsing a briefing he hoped to make to incoming President Barack Obama aides.
[22] According to Glaberson, Hartmann declined to respond to the reports of his briefing rehearsals, but he did issue a statement: "grateful for his strong, focused and effective leadership during these dangerous and challenging times.