During his youth, Hanley sold peanuts at Fenway Park and attended Mission Hill Grammar School.

During their tenure at Massport, King and Hanley worked on immensely expanding Boston's Logan Airport.

Hanley was praised by Massport board member John Larkin Thompson for his management of the port authority's financial affairs.

When King was fired by the Massachusetts Port Authority Board of Directors in 1974, Hanley served as interim executive director for several months before leaving to start a private tax law practice with John J. Egan, the father-in-law of King's brother.

[2] When King was elected governor in 1978, Hanley left his lucrative law practice to accept the lower paying job of Secretary of Administration and Finance.

[2][3] He received praise for accurate revenue projections and for being an even-tempered but tough financial manager during the turmoil that came after Proposition 2½ was adopted.

[2][3] However, he was criticized for not being able to cut enough from the state budget to achieve King's campaign promise of rolling taxes back by $500 million.

[4] In November 1981, it was reported that Hanley would resign from the cabinet due to his concern over the state of his tax business following Egan's death.

During his tenure, Hanley opposed Turnpike Authority using its bonding power to finance the Central Artery/Tunnel Project (better known as the Big Dig).