The phrase "a long time advisor" is correct and usable in written English.
It can be used to describe someone who has been providing advice or guidance for an extended period.
Example: "She has been a long time advisor to the board, offering valuable insights and expertise."
Alternatives: "a longtime advisor" or "a veteran advisor".
He has been a long-time advisor to former President Bill Clinton.
Buffett, a long-time advisor to and supporter of Obama, is giving one such company a lift across the border, putting himself immediately in the middle of a political gunfight.
Leo dedicated his life to Jewish community service and worked with UJA-Federation of Greater New York and then as a long time Religious Advisor to Riverside Gordon Memorial Chapels in Southern Florida.
Pashtum father and Tajik mother, he was a long time Shah Massud advisor and has already served as foreign minister in the first Karzai government.
"This is a long time coming," Manuel Montes, senior advisor on finance and development at the South Centre, an intergovernmental think tank based in Geneva, told VICE News.
Kim Burrell's words only made me want to seek support so I turned to a long time friend and spiritual advisor, Pastor Floretta Watkins.
Even if you've been with your advisor for a long time, if it's not the right fit any more he or she will understand (and if they don't, that could be a bad sign in itself!).
People with learning disabilities have felt ostracised from the voting process for a long time, says Tracey Garcia, the involvement and engagement advisor for Dimensions, a not for profit organisation that gives support to people with learning disabilities.
At the Hofstra University Conference on the George W. Bush presidency I was on a panel discussing Bush education policy with Anne-Imelda Radice, Chief of Staff to the Secretary of the United States Department of Education from 2003-2005 and Edward Rollins, a long time Republican Party political operative and a former advisor to President Ronald Reagan.
"Abe Foxman has been a friend and advisor of mine for a long time," Biden said in a statement provided to The Huffington Post.
Iranian military advisors have been in Syria for a long time, points out Aron Lund, editor of the Carnegie Endowment for International Peace's Syria in Crisis.
